Focus Mode Causes Notes to Disappear

### Expected
I expected that when I toggle the Focus Mode, my notes would remain visible or be restored after exiting Focus Mode.

### Observed
When I toggle the Focus Mode, all my notes disappear, and the only way to restore them is to restart the application.

### Reproduced
1. Open the Simplenote app.
2. Click on the "Toggle Focus Mode" option.
3. Observe that all notes disappear.


### Where did you see the bug
- System Make: Apple
- System Model: macOS
- OS: Monterey
- OS version: 12.7.6
- Browser (if applicable): N/A
- Browser version (if applicable): N/A
- Simplenote app version: 2.22.2

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The last version that works normally is 2.21.0.

Reproduce the issue in Simplenote 2.22.2 by using the “Toggle Focus Mode” option, then compare the behavior with version 2.21.0, which is reported to work normally. Trace the Focus Mode toggle path and verify that notes remain visible or return after exiting Focus Mode without restarting the application.

Written by the indexing model from the issue text.