Adds a function to each 'wheel' DataPacket sent to the framework so it can signal whether to `allowPlatformDefault` or not.

The current default is to always `preventDefault` on browser events that get sent to the framework.

This PR enables the framework to call a method on the `DataPacket`s to `allowPlatformDefault: true`, if the framework won't handle the Signal (signals are handled synchronously on the framework).

This lets the engine "wait" for the framework to decide whether to `preventDefault` on a `wheel` event or not.

## Issues

* Needed for: flutter/flutter#139263

## Tests

* Added unit tests for the feature in the engine repo, veryfing whether the event has had its `defaultPrevented` or not.
* Manually tested in a demo app (see below)

## Demo

* https://dit-multiview-scroll.web.app

<details>
<summary>

## Previous approaches

</summary>

1. Add a `handled` bool property to `PointerDataPacket` that the framework can write to (brittle)
2. Modifications to the `PlatformDispatcher` so the framework can `acknowledgePointerData` with a `PointerDataResponse` (fffffatttt change)
3. `acknowledge` function in `PointerDataPacket`

</details>

> [!IMPORTANT]
> * Related: flutter/flutter#145500

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

…flutter#145500)

…flutter#145500)

flutter/flutter@32081aa...14df7be

2024-06-11 [email protected] Revert "Add tests for scaffold drawer and end drawer" (flutter/flutter#150045)
2024-06-11 [email protected] Add tests for scaffold drawer and end drawer (flutter/flutter#149383)
2024-06-11 [email protected] Add high-contrast theme (flutter/flutter#149779)
2024-06-11 [email protected] Manual Pub Roll (flutter/flutter#150025)
2024-06-10 [email protected] [docs] Per-platform desktop triage instructions (flutter/flutter#150019)
2024-06-10 [email protected] Fix copy-paste-o in MethodChannel.invokeListMethod doc (flutter/flutter#149976)
2024-06-10 [email protected] Unpin `camera_android` and remove its only usage (flutter/flutter#150017)
2024-06-10 [email protected] Fixes a bug where NavigatorState.pop does not consider any possible sâ�¦ (flutter/flutter#150014)
2024-06-10 98614782+auto-submit[bot]@users.noreply.github.com Reverts "Reland: [CupertinoActionSheet] Match colors to native (#149568) (#150015)" (flutter/flutter#150021)
2024-06-10 [email protected] Reland: [CupertinoActionSheet] Match colors to native (#149568) (flutter/flutter#150015)
2024-06-10 [email protected] Temporarily run Mac_arm64 framework_tests_misc on only Mac-13 (flutter/flutter#150009)
2024-06-10 [email protected] Fixes TextField hinttext in a11y_assessment (flutter/flutter#150007)
2024-06-10 [email protected] Use const bool.fromEnvironment("dart.tool.dart2wasm") to detect dart2wasm (flutter/flutter#149996)
2024-06-10 [email protected] Roll Packages from 8a2c4e4 to e95fe4a (3 revisions) (flutter/flutter#149997)
2024-06-10 [email protected] [web] Notify engine of handled PointerScrollEvents. (flutter/flutter#145500)
2024-06-10 [email protected] Cut no-longer-accurate microtask reference in finalizeTree doc (flutter/flutter#149941)
2024-06-10 [email protected] Update hasTrailingSpaces (flutter/flutter#149698)
2024-06-10 [email protected] [web] Change `--web-renderer` default from `auto` to `canvaskit` (flutter/flutter#149773)
2024-06-10 [email protected] Retain the toString method for subclasses of Key in profile/release mode (flutter/flutter#149926)
2024-06-10 [email protected] Remove package:platform from issue template (flutter/flutter#149995)
2024-06-10 [email protected] Revert "[CupertinoActionSheet] Match colors to native (#149568)" (flutter/flutter#149998)

If this roll has caused a breakage, revert this CL and stop the roller
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…flutter#145500)

#183302)

## This PR
- Fixes #152588


## Some history and reasoning
### Root cause
The bug was introduced in PR #145500, which fixed issue #139263 by
ensuring that the Web engine knows when a scroll event is not handled by
Flutter. This allows the browser to perform default actions like page
scrolling or back/forward navigation. Without this, Flutter might
"swallow" events it doesn't use, leading to a "dead" feel on the web.

### Why reverting is safe and won't regress Issue #139263
Reverting the manual `respond(true)` calls in Scrollable is safe because
`PointerSignalResolver` (the centralized mediator for these events)
already has the logic to notify the engine. More specifically,
`PointerSignalResolver.resolve` calls
`event.respond(allowPlatformDefault: true)` if and only if no widget in
the hit-test tree registered interest in the event.

Moving this responsibility back to the `PointerSignalResolver` ensures
that:
1. If **_any_** widget handles the event: It registers with the
resolver, and `respond(true)` is **_not called_**.
2. If **_no_** widget handles the event: No one registers, and the
resolver **_calls_** `respond(true)` at the end of the dispatch cycle.

The current bug exists because `Scrollable` was trying to be too helpful
by calling `respond(true)` based only on its local state, which
overrides any handling done by other widgets in the hierarchy.

### Testing and verifying

A new regression test was created that highlight how the respond calls
should work in nested `Scrollable` elements.

The "fallback" nature of `PointerSignalResolver` is already 
1. documented in `pointer_signal_resolver.dart`:
```dart
  void resolve(PointerSignalEvent event) {
    if (_firstRegisteredCallback == null) {
      assert(_currentEvent == null);
      // Nothing in the framework/app wants to handle the `event`. Allow the
      // platform to trigger any default native actions.
      event.respond(allowPlatformDefault: true);
      return;
    }
    // ... handles the registered callback ...
  }

```
2. tested in `pointer_signal_resolver_test.dart`:
```dart
  test('Resolving with no entries should notify engine of no-op', () {
    var allowedPlatformDefault = false;
    final tester = PointerSignalTester();
    tester.event = PointerScrollEvent(
      onRespond: ({required bool allowPlatformDefault}) {
        allowedPlatformDefault = allowPlatformDefault;
      },
    );
    tester.resolver.resolve(tester.event);
    expect(
      allowedPlatformDefault,
      isTrue,
      reason: 'Should have called respond with allowPlatformDefault: true',
    );
  });

```

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.