Error `PushNotificationTranslation matching query does not exist`

[MizukiTemma]

Describe the Bug

This will be a supplement to #2722

Steps to Reproduce

1. Create a region which has only English as their language
2. Create a push notification in this region and select "Use main language..." and check "Stadt Augsburg"
3. Save and send
4. See the error

No unexpected error occrus while creating and sending a push notification in Augsburg with only German translation and the English-only region selected (basically, otherway around). In this case you get an warning that the title for English translation is required and everything is fine, thanks to #2727

I know such a case like this will mostlikely not exist in the live system since the regions have usually German as default language (or at least one of their languages), but that's only an assumption 😅 🙈

Expected Behavior

Warning shown that title for other languages are required.

Actual Behavior

Error

Additional Information

Traceback