Desktop: Accessibility: Fix global keyboard shortcuts are ignored when the sidebar has focus

[personalizedrefrigerator]

Summary

Fixes a bug that prevented using global shortcuts (e.g. ctrl-shift-b = jump to note body) from the sidebar in some cases.

This pull request fixes a regression from #13469. With #13469, pressing a single, unmodified alphanumeric/symbol key on the keyboard should jump to the notebook, tag, or header starting with that key.

Reported in comment.

Testing plan

Fedora 42 Linux:

1. Create a notebook with title "B" (to match the keyboard shortcut).
2. Switch to a different notebook that contains notes.
3. Move focus to the notebook list.
4. Press ctrl-shift-b.
5. Verify that focus moves to the note body.
6. Move focus back to the notebook list.
7. Press shift-b.
8. Verify that focus moves to the notebook created in step 1.