Request audio focus for video playback so background music pauses (#2151)

## Description
The video player passes false to setAudioAttributes (since #1258 I
think), as ExoPlayer never requests audio focus. This will pass `true`.

### Related issues
#447, #1258.

### Testing
Not tested on a device.

### Screenshots
Not applicable

### AI or LLM usage
None.

---------

Co-authored-by: Damontecres <damontecres@gmail.com>

app/src/main/java/com/github/damontecres/wholphin/services/PlayerFactory.kt

@@ -182,8 +182,9 @@ class PlayerFactory
                                         AudioAttributes
                                             .Builder()
                                             .setContentType(C.AUDIO_CONTENT_TYPE_MOVIE)
+                                            .setUsage(C.USAGE_MEDIA)
                                             .build(),
-                                        false,
+                                        true,
                                     )
                                 }
                             }