New user workflow problem: Trying to send a message from gotify android before any apps are defined on server causes hang and crash of android app

Trying to push a message out from the android app before any applications are defined on the gotify server causes the android app to hang until android ui offers to kill it.

Once an application has been defined on the server, the app dropdown on android's push message screen can no longer be set to a null selection, and it is no longer possible to trigger this issue through the app's ui.

As a side effect, if the user accepts android's "kill hanging app" prompt, this also can put the gotify app to get in a state where the background listener is dead despite the main gotify app running in the foreground. This can lead to the app seeming unable to receive push notifications for a new user,