[Win/Ubuntu] Restoring app window size from maximized can spoil note layout

### Expected
Window resize should not affect the note layout

### Observed
When restoring app window size from maximized, the note content will be displayed in `one char per line` style:

https://user-images.githubusercontent.com/73365754/110806786-1176de80-828b-11eb-88b7-7b2ed83ec94d.mov

### Reproduced
1. Easier to reproduce with `View` ~> `Line Length` ~> `Narrow`
2. Maximize the window
3. Select some note with text
4. Restore the window size with a button via window header doubleclick

### Where did you see the bug
- System Make: Parallels Desktop on MBP 16"
- System Model: Parallels Desktop on MBP 16"
- OS: Windows | Ubuntu
- OS version: 10 Home 20H2 build 19042.508 | 20.04.1 LTS
- Browser (if applicable): x
- Browser version (if applicable): x
- Simplenote app version: 2.8.0-beta2 desktop

Start by reproducing the problem on Windows or Ubuntu using View > Line Length > Narrow, then maximize and restore a window containing a note. Trace the window-restore and note-layout handling; done means restoring the window no longer displays note content one character per line.

Written by the indexing model from the issue text.