fix(video-quality-dialog): Initial value.

Fixes an issue when the video quality dialog is opened for first time
and config.videoQuality.persist is true there isn't any selected option.

react/features/video-quality/middleware.js

     case SET_CONFIG: {
         const state = getState();
         const { videoQuality = {} } = state['features/base/config'];
+        const { persistedPrefferedVideoQuality } = state['features/video-quality-persistent-storage'];
 
-        if (videoQuality.persist) {
-            dispatch(
-                setPreferredVideoQuality(
-                    state['features/video-quality-persistent-storage'].persistedPrefferedVideoQuality));
+        if (videoQuality.persist && typeof persistedPrefferedVideoQuality !== 'undefined') {
+            dispatch(setPreferredVideoQuality(persistedPrefferedVideoQuality));
         }
 
         break;