ao_pipewire: set media role during init()

wireplumber uses the media role when the node is first created.
To have the property available at this point reliably we need to set it
directly when creating the stream/node.

audio/out/ao_pipewire.c

@@ -553,7 +553,7 @@ static int init(struct ao *ao)
     struct pw_properties *props = pw_properties_new(
         PW_KEY_MEDIA_TYPE, "Audio",
         PW_KEY_MEDIA_CATEGORY, "Playback",
-        PW_KEY_MEDIA_ROLE, "Movie",
+        PW_KEY_MEDIA_ROLE, ao->init_flags & AO_INIT_MEDIA_ROLE_MUSIC ?  "Music" : "Movie",
         PW_KEY_NODE_NAME, ao->client_name,
         PW_KEY_NODE_DESCRIPTION, ao->client_name,
         PW_KEY_APP_NAME, ao->client_name,