Player/handleIntent: fix enqueue if player not running

In 063dcd41e5 I falsely claimed that the
fallthrough case is always degenerate, but it kinda somehow still
worked because if you long-click on e.g. the popup button, it would
call enqueue, but if nothing was running yet it would fallthrough to
the very last case and start the player with the video.

So let’s return to that and add a TODO for further refactoring in the
future.

app/src/main/java/org/schabi/newpipe/player/Player.java

@@ -394,8 +394,12 @@ public final class Player implements PlaybackListener, Listener {
                         return;
                     }
                     playQueue.append(newQueue.getStreams());
+                    return;
                 }
-                return;
+
+                // TODO: This falls through to the old logic, there was no playQueue
+                // yet so we should start the player and add the new video
+                break;
             }
             case EnqueueNext -> {
                 if (playQueue != null) {
@@ -405,8 +409,12 @@ public final class Player implements PlaybackListener, Listener {
                     }
                     final PlayQueueItem newItem = newQueue.getStreams().get(0);
                     newQueue.enqueueNext(newItem, false);
+                    return;
                 }
-                return;
+
+                // TODO: This falls through to the old logic, there was no playQueue
+                // yet so we should start the player and add the new video
+                break;
             }
             case TimestampChange -> {
                 final TimestampChangeData dat = intent.getParcelableExtra(PLAYER_INTENT_DATA);