Repository: flutter
Issue: SelectableRegionState.startGlyphHeight / endGlyphHeight throws null
Labels: c: crash,framework,a: production,P2,needs repro info,f: selection,team-framework,triaged-framework

## Steps to Reproduce
These are errors from Crashlytics, I don't know how to reproduce them. I've tried with an Android 13 emulator.
Crashlytics reports issues only on Android 11, 12 and 13.

The widget probably causing this is a ScrollView. I'm guessing the selected region ends up out of the viewport, but I haven't managed to reproduce the issue despite this information.

<details>
<summary>Firebase logs</summary>

```

Fatal Exception: io.flutter.plugins.firebase.crashlytics.FlutterError: Null check operator used on a null value. Error thrown Instance of 'ErrorDescription'.
       at SelectableRegionState.endGlyphHeight(selectable_region.dart:1006)
       at SelectableRegionState.contextMenuAnchors(selectable_region.dart:907)
       at new AdaptiveTextSelectionToolbar.selectableRegion(adaptive_text_selection_toolbar.dart:169)
       at SelectionArea._defaultContextMenuBuilder(selection_area.dart:96)
       at SelectableRegionState._onAnyDragEnd.<fn>(selectable_region.dart:537)
       at SelectionOverlay.showToolbar.<fn>(text_selection.dart:1344)
       at ContextMenuController.show.<fn>(context_menu_controller.dart:59)
       at _OverlayEntryWidgetState.build(overlay.dart:259)
       at StatefulElement.build(framework.dart:5080)
       at ComponentElement.performRebuild(framework.dart:4968)
       at StatefulElement.performRebuild(framework.dart:5133)
       at Element.rebuild(framework.dart:4690)
       at BuildOwner.buildScope(framework.dart:2743)
       at WidgetsBinding.drawFrame(binding.dart:863)
       at RendererBinding._handlePersistentFrameCallback(binding.dart:381)
       at SchedulerBinding._invokeFrameCallback(binding.dart:1289)
       at SchedulerBinding.handleDrawFrame(binding.dart:1218)
       at SchedulerBinding._handleDrawFrame(binding.dart:1076)

---

Fatal Exception: io.flutter.plugins.firebase.crashlytics.FlutterError: Null check operator used on a null value. Error thrown Instance of 'ErrorDescription'.
       at SelectableRegionState.startGlyphHeight(selectable_region.dart:1001)
       at SelectableRegionState.contextMenuAnchors(selectable_region.dart:906)
       at new AdaptiveTextSelectionToolbar.selectableRegion(adaptive_text_selection_toolbar.dart:169)
       at SelectionArea._defaultContextMenuBuilder(selection_area.dart:96)
       at SelectableRegionState._onAnyDragEnd.<fn>(selectable_region.dart:537)
       at SelectionOverlay.showToolbar.<fn>(text_selection.dart:1344)
       at ContextMenuController.show.<fn>(context_menu_controller.dart:59)
       at _OverlayEntryWidgetState.build(overlay.dart:259)
       at StatefulElement.build(framework.dart:5080)
       at ComponentElement.performRebuild(framework.dart:4968)
       at StatefulElement.performRebuild(framework.dart:5133)
       at Element.rebuild(framework.dart:4690)
       at BuildOwner.buildScope(framework.dart:2743)
       at WidgetsBinding.drawFrame(binding.dart:863)
       at RendererBinding._handlePersistentFrameCallback(binding.dart:381)
       at SchedulerBinding._invokeFrameCallback(binding.dart:1289)
       at SchedulerBinding.handleDrawFrame(binding.dart:1218)
       at SchedulerBinding._handleDrawFrame(binding.dart:1076)

```

</details>

<details>
  <summary>Logs</summary>

```

[√] Flutter (Channel stable, 3.7.6, on Microsoft Windows [Version 10.0.19044.2604], locale fr-BE)
    • Flutter version 3.7.6 on channel stable at D:\Code\Flutter\sdk\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 12cb4eb7a0 (2 weeks ago), 2023-03-01 10:29:26 -0800
    • Engine revision ada363ee93
    • Dart version 2.19.3
    • DevTools version 2.20.1

[√] Windows Version (Installed version of Windows is version 10 or higher)

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at C:\Users\user\AppData\Local\Android\sdk
    • Platform android-33, build-tools 30.0.3
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 11.0.12+7-b1504.28-7817840)
    • All Android licenses accepted.

[√] Android Studio (version 2021.2)
    • Android Studio at C:\Program Files\Android\Android Studio
    • 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 11.0.12+7-b1504.28-7817840)

[√] VS Code (version 1.76.2)
    • VS Code at C:\Users\user\AppData\Local\Programs\Microsoft VS Code
    • Flutter extension version 3.44.0

[√] VS Code, 64-bit edition (version 1.74.3)
    • VS Code at C:\Program Files\Microsoft VS Code
    • Flutter extension version 3.44.0

[√] Connected device (1 available)
    • sdk gphone64 x86 64 (mobile) • emulator-5554 • android-x64 • Android 13 (API 33) (emulator)

[√] HTTP Host Availability
    • All required HTTP hosts are available

• No issues found!

```

</details>