Tag deletion from tags list should affect the notes in `Trash` too

Same issue for iOS [here](https://github.com/Automattic/simplenote-ios/issues/1234)

### Expected
If we delete a tag from the tags list, the tag should also be removed from notes in Trash (happens in Electron and Android)

### Observed
https://user-images.githubusercontent.com/73365754/114037860-06af6980-988a-11eb-9001-44492858187d.mov

### Reproduced
1. Open a note with no tags
2. Add a new unique tag to the note
3. Move note to trash
4. Delete the tag mentioned in step 2
5. Open Trash, and open the trashed note ~> it will still contain the tag
6. Restore the note ~> note has a tag, but tag does not appear in tags list
7. Click the tag in note editor ~> tag appears is tags list

Make|Model|macOS Version|App Version
-|-|-|-
Apple|MBP 16"|11.2.3|2.11 (11229)

Start by reproducing the seven-step case in the macOS app, then compare the tag-deletion behavior with Electron and Android, as the issue suggests. Trace the tag deletion flow and how trashed notes retain tags. Done means deleting a tag removes it from notes in Trash and restoring a note does not resurrect a tag absent from the tags list.

Written by the indexing model from the issue text.