Use the drained callback on the playback stream

This may be more correct than using the "paused" event.

pipewire/qubes-pw-module.c

@@ -1016,7 +1016,8 @@ static void stream_state_changed(void *data, enum pw_stream_state old,
         return;
     case PW_STREAM_STATE_PAUSED:
         pw_log_debug("%s paused", name);
-        set_stream_state(stream, false);
+        if (!qubes_stream_is_playback(stream))
+            set_stream_state(stream, false);
         break;
     case PW_STREAM_STATE_STREAMING:
         pw_log_debug("%s streaming", name);
@@ -1268,6 +1269,11 @@ static void stream_param_changed(void *data, uint32_t id, const struct spa_pod *
     }
 }
 
+static void playback_stream_drained(void *data)
+{
+    set_stream_state(data, false);
+}
+
 static const struct pw_stream_events capture_stream_events = {
     .version = PW_VERSION_STREAM_EVENTS,
     .destroy = stream_destroy,
@@ -1290,6 +1296,7 @@ static const struct pw_stream_events playback_stream_events = {
     .add_buffer = NULL,
     .remove_buffer = NULL,
     .process = playback_stream_process,
+    .drained = playback_stream_drained,
 };
 
 static void core_error(void *data, uint32_t id, int seq, int res, const char *message)