UI: Fix possible source reference leakage

This would fail to release the reference if the 'direct' parameter was
used.

Closes jp9000/obs-studio#1116

UI/window-basic-main-transitions.cpp

@@ -341,7 +341,7 @@ void OBSBasic::TransitionToScene(OBSSource source, bool force, bool direct,
 			TransitionFullyStopped();
 	}
 
-	if (usingPreviewProgram && sceneDuplicationMode && !direct)
+	if (usingPreviewProgram && sceneDuplicationMode)
 		obs_scene_release(scene);
 }