Notes multiselection is discarded after switching the apps

Labelled this as a bug, because it can potentially cause the loss of time for the user

### Expected
Notes selection is not lost after app is minimized/sent to background. E.g. see native Messages.

### Observed
When notes are selected in edit mode, and the app is minimized/someone calls/user switches the app, the selection is lost:

https://user-images.githubusercontent.com/73365754/120713976-4c279600-c4cb-11eb-93bc-a9495e7b5480.MP4

### Reproduced
1. Have some notes
2. Open All Notes
3. Start `Edit mode`
4. Select some notes
5. Switch to the other app and back ~> selection is lost

Make|Model|iOS Version|App Version
-|-|-|-
iPhone | XR | 14.4.2 |4.37.0.0 Nü

Reproduce the issue in All Notes by entering Edit mode, selecting notes, switching to another app, and returning. Trace the selection state around app minimization or backgrounding. Done means the selected notes remain selected after returning, including during an interruption such as an incoming call.

Written by the indexing model from the issue text.