Mobile: Drawing: Fix clicking "cancel" after starting a new drawing in editing mode creates an empty resource

[personalizedrefrigerator]

Summary

This pull request fixes an issue related to this forum post. Previously,

1. opening a note in edit mode,
2. clicking "Attach drawing", and
3. clicking "Close"

would attach an empty drawing to the current note, which may cause sync to fail for some sync targets.

Testing plan

1. Create a new note.
2. Verify that the note editor (and not the viewer) is open.
3. Open the note action menu.
4. Click "Draw picture".
5. Click "Close".
6. Verify that no drawing has been added.
7. Open the note action menu.
8. Click "Draw picture".
9. Draw something.
10. Click "Close".
11. Click "Save changes".
12. Verify that an image has been inserted.
13. Move the cursor to the beginning of the editor.
14. Open the note action menu.
15. Click "Draw picture".
16. Draw something.
17. Click "save".
18. Verify that "save" is greyed out/disabled.
19. Click "Close".
20. Verify that a new drawing has been added to the beginning of the note.
21. Switch to the note viewer.
22. Open the note action menu.
23. Click "Draw picture".
24. Draw something.
25. Click "close".
26. Click "Discard changes".
27. Verify that no new drawing has been attached.
28. Open the note action menu.
29. Click "Draw picture".
30. Draw something.
31. Click "save", then "close".
32. Verify that a new drawing has been added to the end of the note.

This has been tested successfully on:

• An iOS 17 simulator.
• Web (Safari on MacOS).
• Android 13

[personalizedrefrigerator]

A new save-and-close action was added to fix an issue on iOS where clicking "Close" then "Save changes" would attach duplicates of a drawing. This saves before the editor starts loading (rather than during). See #10431.