Holding backspace on Android sporadically fails to delete text sequentially

Description

When focused on a text block, pressing and holding Backspace does not delete text across multiple blocks as expected. At times, the deletion will simply stop after emptying one text block and moving focus to the next; other times, it will erroneously place the cursor at the beginning of the newly focused text block instead of the end.

When holding Backspace, each word in the text block should be deleted. Once the block is empty, the block should be removed, the previous block should be focused with the cursor at the end of the text, and deletion should continue as long as the Backspace key is pressed.

Step-by-step reproduction instructions

1. Open a post with a decent amount of text on Android.
2. Focus a text block that follows other text blocks.
3. Move the cursor to the end of the text block.
4. Press and hold the Backspace key.

Screenshots, screen recording, code snippet

https://github.com/user-attachments/assets/850022a2-6ce5-47a6-a491-3ef3590a8369

Environment info

• Jetpack 25.8
• Samsung Galaxy S20, Android 13

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

Start by reproducing the issue on Android 13 with a Samsung Galaxy S20, using multiple text blocks and holding Backspace from the end of a block. Trace the editor's focus and deletion handling as an empty block is removed. Done means deletion continues across blocks, the previous block is focused with the cursor at its end, and the behavior is covered by a regression test if the relevant test entry point is found.