Repository: flutter
Issue: TextSpan do not render the font weight correctly
Labels: engine,a: typography,has reproducible steps,P2,team-engine,triaged-engine,found in release: 3.16,found in release: 3.18

### Steps to reproduce

In the next example the weight of the word 'of' is not changing. The issue is both on iOS and Android.



### Expected results

I expected to have a weight of 100 applied to the word 'of'

### Actual results

The weight is inherited from the parent even if I specified a different one in the child.


### Code sample

<details open><summary>Code sample</summary>

```dart
MaterialApp(
      home: SafeArea(
        child: Scaffold(
          body:  RichText(
            text: TextSpan(
              text: 'Scanning box: ',
              style: GoogleFonts.poppins(
                textStyle: const TextStyle(
                  color: Colors.black,
                  fontWeight: FontWeight.w900,
                  overflow: TextOverflow.ellipsis,
                  fontSize: 16,
                ),
              ),
              children: const [
                TextSpan(
                  text: '2',
                  style: TextStyle(color: Colors.orange),
                ),
                TextSpan(
                  text: ' of ',
                  style: TextStyle(
                    fontWeight: FontWeight.w100,
                    color: Colors.grey,
                  ),
                ),
                TextSpan(
                  text: '5',
                  style: TextStyle(color: Colors.orange),
                ),
              ],
            ),
          ),
        ),
      ),
    );
```

</details>


### Screenshots or Video

<details open>
<summary>Screenshots / Video demonstration</summary>

<img width="214" alt="image" src="https://github.com/flutter/flutter/assets/49788518/9621b52d-1f6a-46cb-a8f6-4a5593273c93">

</details>


### Logs

_No response_

### Flutter Doctor output

<details open><summary>Doctor output</summary>

```console
[✓] Flutter (Channel stable, 3.16.4, on macOS 14.2.1 23C71 darwin-arm64, locale en-RO)
    • Flutter version 3.16.4 on channel stable at /Users/ovidiuusvat/development/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 2e9cb0aa71 (3 weeks ago), 2023-12-11 14:35:13 -0700
    • Engine revision 54a7145303
    • Dart version 3.2.3
    • DevTools version 2.28.4

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.1)
    • Android SDK at /Users/ovidiuusvat/Library/Android/sdk
    • Platform android-33, build-tools 33.0.1
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.7+0-17.0.7b1000.6-10550314)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 15.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 15C65
    • CocoaPods version 1.14.3

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2023.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 17.0.7+0-17.0.7b1000.6-10550314)

[✓] VS Code (version 1.83.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.74.0

[✓] Connected device (4 available)
    • sdk gphone64 arm64 (mobile) • emulator-5554                        • android-arm64  • Android 13 (API 33) (emulator)
    • iPhone 15 Pro Max (mobile)  • F091BEA2-67E5-40CA-A5F1-E93BEA1D19F0 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-17-2 (simulator)
    • macOS (desktop)             • macos                                • darwin-arm64   • macOS 14.2.1 23C71 darwin-arm64
    • Chrome (web)                • chrome                               • web-javascript • Google Chrome 109.0.5414.119

[✓] Network resources
    • All expected network resources are available.


```

</details>