Disabling "Update notifications" in the per app settings does not get saved

[jesselai]

In recent versions (1.10.51 was tested), disabling the updating notifications in the per app settings doesn't seem to actually get saved. This used to work in previous versions (1.10.44 at least).

Steps to reproduce:

1. Click on an app in the list to bring up the details
2. Click on the overflow button (top right)
3. Pick the "Settings" option to bring up the per app settings
4. Uncheck the "Update notifications" checkbox.
5. Click OK to close the menu.
6. Repeat steps 2 & 3 to go back into the settings menu. The box is still checked.