UI zoom in reverts after closing app

Zooming in UI with Ctrl + , will revert to default after closing and reopening app. (I'm using 2.6.0-beta2 version.)
### Expected

Stay on adjusted zoom level after closing and reopening.
### Observed

### Reproduced

1. open the app
2. zoom in and close the app
3. now reopen and it's on default zoom.

### Where did you see the bug

- OS: Linux amd64
- OS version: 5.10.11
- Simplenote app version: 2.6.0-beta2 appimage

Start by reproducing the three steps in the Simplenote app on Linux with version 2.6.0-beta2. Trace where the UI zoom level is changed and persisted across app shutdown, then verify that reopening the app retains the adjusted level.

Written by the indexing model from the issue text.