participants: fix accessing the local participant ID

getLocalParticipant returns a participant object stored in Redux, not a
JitsiParticipant object.

react/features/base/participants/middleware.js

 
                 });
         } else {
-            const localParticipantId = getLocalParticipant(store.getState).getId();
+            const localParticipantId = getLocalParticipant(store.getState).id;
 
             // We left the conference, the local participant must be updated.
             _e2eeUpdated(store, conference, localParticipantId, false);