iOS: Accessibility: Fix to-do completion status can't be changed from the note list

[personalizedrefrigerator]

Summary

This pull request fixes an accessibility issue on iOS — the checkbox for note list items and the note list item description were both included in the same <Pressable. Although Android allowed focusing the checkbox and note list item title individually, this was not possible on iOS. As a result, it was previously necessary to open a note before its completion status could be changed.

This pull request moves the to-do checkbox outside of the pressable item that opens a note. To continue applying the press-related opacity animation to both the checkbox and the note title, a new MultiTouchableOpacity component is created. When the main touchable component in a MultiTouchableOpacity is pressed, the opacity animation is applied to both the main touchable and any additional components.

Testing plan

iOS 18, Android 13

1. Create two or more to-dos.
2. Move the focus to the top of the note list.
3. Navigate through the to-dos.
   • Verify that the label for each checkbox includes a description of its associated note (e.g. to-do: Test, unchecked on iOS, not checked, to-do: Test, checkbox on Android).
   • Note: On Android, this change moves the checkbox before the "opens note" button in the focus order.
4. Move focus to the first checkbox and double-tap.
5. Verify that the to-do (previously incomplete) is marked as complete.
6. Move focus to the label associated with the to-do.
7. Double-tap.
8. Verify that this opens the to-do in the note viewer.

[personalizedrefrigerator]

Related: #11661