Desktop: Accessibility: Fix multi-note selection menu not tab-focusable

[personalizedrefrigerator]

Summary

This pull request fixes an accessibility bug — previously, selecting multiple notes in the sidebar, then pressing tab had no effect (despite the presence of a menu).

This issue is fixed by removing an unnecessary tab override. Previously, pressing tab from the note list 1) prevented the default browser handling of the tab key and 2) tried to focus the note title input regardless of whether it was visible.

Notes

• To avoid a regression, additional focus/blur selection logic is added. Without it, refocusing the title input with the tab key would select the title input's content, rather than restore the cursor location.
• For now, the shift-tab override remains.

Testing plan

1. Ensure that several to-dos and notes are visible in the note list.
2. Focus a note in the note list.
3. Press tab.
4. Verify that the note title has focus and that the cursor is at the end of the input.
5. Focus the note list by pressing shift-tab.
6. Select multiple notes using shift and the arrow keys.
7. Verify that the note selection menu is visible.
8. Press tab.
9. Verify that the note selection menu has focus.
10. Select just one note.
11. Press tab.
12. Verify that the note title is focused. Select the first letter.
13. Press shift-tab, then tab.
14. Verify that focus is restored to the first character.

This has been tested successfully on MacOS Sonoma.

[personalizedrefrigerator]

Related to #10795.