fix: app update error notification always disappeared

[cuong-tran]

How to reproduce the issue

1. Try downloading the app update on a slow network - Or purposely decrease network.client.callTimeout to just 1-3 seconds.
2. Wait for the timeout exception to occur (could be any other exception that could be manipulated to occur)

Expect

• The Download Error notification should be shown after the Downloading notification hides.

Actual

• The Downloading notification hides and there are no more notification.

Reason

• AppUpdateDownloadJob foreground is set tied to Notifications.ID_APP_UPDATER
• The Download Error notification also use Notifications.ID_APP_UPDATER - debug shows that it is actually called to show
• But when Job is done (i.e. download stoped for any reason), the whole Notifications.ID_APP_UPDATER is closed and hence clearing the Download Error notification.