This PR does three things:

• Re-enables url_launcher_web testing in web-platform_tests in the stable channel.
• Fixes the tests that were failing in url_launcher_web by adding an "await" on the tester in between tests (this is odd, and only required in stable with Chrome 98, so there might be some weird interaction with that combination)
• Fixes a google_maps_web test that started failing. It seems that we used to be able to move the "center" of a Map that was being mocked, but now it seems that the map needs a proper projection. Moved the failing test case to a test that has an actual map widget being rendered.

Fixes flutter/flutter#121161

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages repo does use dart format.)
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I listed at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is exempt from version changes.
• I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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