Move last sign in update to ProcessLifecycleOwner onCreate

[SUPERCILEX]

Currently, we do it whenever the user is signed in:

Robot-Scouter/library/core-data/src/main/java/com/supercilex/robotscouter/core/data/Database.kt

Lines 163 to 168 in c28662f

	FirebaseAuth.getInstance().addAuthStateListener {
	val user = it.currentUser
	if (user != null) {
	updateLastLogin.run()
	}
	}

This is a problem because something like app indexing will periodically wake up our app even if the user isn't actually using it. ProcessLifecycleOwner will make sure at least one activity is open before we update user presence.