Make conversation notification sound configurable

[RankoR]

Closes #298

[inthewaves]

BugleActionToasts#onMessageReceived is called inside of a database transaction (https://github.com/GrapheneOS/Messaging/blob/main/src/com/android/messaging/datamodel/action/ReceiveSmsMessageAction.java#L137-L155), so InConversationSound.playIfEnabled(conversationId); is being called inside of one

[inthewaves]

This can block inside of a Messaging app database transaction waiting for mediaserver to finish: https://github.com/GrapheneOS/platform_frameworks_av/blob/7a46fb37eae0e57496e4242007449ca56c957ce7/media/libmedia/mediaplayer.cpp#L305-L326

RingtoneManager.getRingtone(...)
-> Ringtone.createLocalMediaPlayer()
  -> MediaPlayer.prepare() (documentation for this says "blocks until MediaPlayer is ready for playback")
    -> JNI native MediaPlayer::prepare()
      -> Binder: service-side player.prepareAsync()
      -> mSignal.wait(mLock)

[inthewaves]

RingtoneManager.getRingtone(context, uri) creates a local MediaPlayer and synchronously calls MediaPlayer.prepare()

Although this looks like a simple variable reassignment in Kotlin, doing this ringtone.audioAttributes recreates/prepares that MediaPlayer again: https://github.com/GrapheneOS/platform_frameworks_base/blob/17/media/java/android/media/Ringtone.java#L161-L168

[inthewaves]

This drops the 5 seconds limit from the old code in BugleNotifications:

        // Stop the sound after five seconds to handle continuous ringtones
        ThreadUtil.getMainThreadHandler().postDelayed(new Runnable() {
            @Override
            public void run() {
                player.stop();
            }
        }, 5000);