This change affects Android and iOS devices using the TextField's context menu. After this change the context menu will fade out when scrolling the text and fade in when the scroll ends. 

If the scroll ends and the selection is outside of the view, then the toolbar will be scheduled to show in a future scroll end. This toolbar scheduling can be invalidated if the `TextEditingValue` changed anytime between the scheduling and when the toolbar is ready to be shown.

This change also fixes a regression where the TextField context menu would not fade when the selection handles where not visible.

When using the native browser context menu this behavior is not controlled by Flutter.

https://github.com/flutter/flutter/assets/948037/3f46bcbb-ba6f-456c-8473-e42919b9d572

Fixes #52425
Fixes #105804
Fixes #52426