Steps to Reproduce

1. Create an app with a Text.rich widget and a TextSpan widget
2. Give the span one child TextSpan with an arbitrary font size significantly larger than the default font size
3. Give the text span a WidgetSpan child containing a Text widget with an arbitrary string and the same large font size
4. Run the app
5. Open the flutter inspector and enable "Show Baselines"

Expected results:
Both strings laid out on the same baseline as Text.rich and even with each other

Actual results:
The string is misaligned with it's parent Text.rich's baseline.

Note in preemptive response to "Why use a WidgetSpan instead of just an InlineSpan directly?":
I need to put an arbitrary box decoration behind a word that's inline with a bunch of other text. This was left out of the reproduction for brevity.

Flutter version 2.8.1, stable branch

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(home: BaselineTest()));
}

class BaselineTest extends StatelessWidget {
  const BaselineTest({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text.rich(
          TextSpan(
            children: [
              TextSpan(text: 'foo', style: TextStyle(fontSize: 30)),
              WidgetSpan(
                child: Text('bar', style: TextStyle(fontSize: 30)),
              ),
            ],
          ),
        ),
      ),
    );
  }
}