Allow TTS notifications to use the alarm stream

[dshokouhi]

Was doing some more testing around TTS notifications. Came to find out that by default they use the MUSIC_STREAM which means that they will ignore the devices ringer mode but not the volume level. By using the ALARM_STREAM we use a separate volume level so it can bypass if media volume is off.

Example:

message: TTS
title: I am speaking
data:
  channel: alarm_stream

channel: alarm_stream is only used to override the default stream.

[dshokouhi]

Added a fix for the following sentry error that was crashing:

java.lang.NullPointerException: Can't toast on a thread that has not called Looper.prepare()
    at com.android.internal.util.Preconditions.checkNotNull(Preconditions.java:157)
    at android.widget.Toast.getLooper(Toast.java:179)
    at android.widget.Toast.<init>(Toast.java:164)
    at android.widget.Toast.makeText(Toast.java:492)
    at android.widget.Toast.makeText(Toast.java:480)
    at io.homeassistant.companion.android.notifications.MessagingService$speakNotification$1.onInit(MessagingService.kt:205)
    at android.speech.tts.TextToSpeech.dispatchOnInit(TextToSpeech.java:863)
    at android.speech.tts.TextToSpeech.initTts(TextToSpeech.java:841)
    at android.speech.tts.TextToSpeech.<init>(TextToSpeech.java:772)
    at android.speech.tts.TextToSpeech.<init>(TextToSpeech.java:751)
    at android.speech.tts.TextToSpeech.<init>(TextToSpeech.java:735)
    at io.homeassistant.companion.android.notifications.MessagingService.speakNotification(MessagingService.kt:183)
    at io.homeassistant.companion.android.notifications.MessagingService.onMessageReceived(MessagingService.kt:119)
    at com.google.firebase.messaging.FirebaseMessagingService.zzc(com.google.firebase:firebase-messaging@@20.1.5:80)
    at com.google.firebase.messaging.zzh.run(com.google.firebase:firebase-messaging@@20.1.5:2)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
    at com.google.android.gms.common.util.concurrent.zza.run
    at java.lang.Thread.run(Thread.java:923)