Annotating getModelState method so it can be used by NowPlaying

Test: none
Bug: 119386757
Change-Id: If4dcd9fae9b693cd040e74d6e7b10be895b46af3

media/java/android/media/soundtrigger/SoundTriggerManager.java

@@ -372,6 +372,7 @@ public final class SoundTriggerManager {
      * @hide
      */
     @RequiresPermission(android.Manifest.permission.MANAGE_SOUND_TRIGGER)
+    @UnsupportedAppUsage
     public int getModelState(UUID soundModelId) {
         if (soundModelId == null) {
             return STATUS_ERROR;