Windows,Linux: Fix keyboard can't add text after certain error/info dialogs are shown

[personalizedrefrigerator]

Summary

This pull request replaces several uses of alert in packages/app-desktop with the async shim.showMessageBox or shim.showErrorDialog equivalents.

This works around this upstream Electron issue related to alert().

Note: See #11241 for a similar change made previously.

Testing plan

Fedora Linux:

1. Click Help > Copy dev mode command to clipboard.
2. Click on the note title input.
3. Type.
4. Verify that the typed text is added to the note title input.
5. Open the webclipper config screen.
6. Click "copy token".
7. Open the "Appearance" tab.
8. Focus the "Editor maximum width" input.
9. Type a number.
10. Verify that the editor maximum width input is updated.
11. Open the note revision viewer.
12. Restore a revision.
13. Verify that it's possible to type text in the title input.
14. Open the encryption config screen.
15. Click "Clear master password".
16. Open the master password dialog.
17. Enter an incorrect password.
18. Click "save".
19. Verify that an error dialog with the message "Master password is not valid. Please try again" and an "OK" button is shown.
20. Enter the correct password and click "save".
21. Disconnect from Joplin Server (e.g. by stopping the Server instance).
22. Right-click on a shared notebook and click "Leave notebook".
23. Click "OK".
24. Verify that it's still possible to edit the note title input.
25. Open settings > appearance.
26. Change a setting.
27. Switch to the "Encryption" tab.
28. In the "This will open a new screen" dialog, click "Ok".
29. Close settings.
30. Verify that it's still possible to edit the note title input.