fix(rn, appNavigate) make sure tracks are created before prejoin

- Create the tracks early, or there will be on audio on iOS on the first
  unmute this includes the unsafe room name screen
- Skip the unsafe room screen if prejoin is disabled, like web

react/features/app/actions.native.ts

         dispatch(setConfig(config));
         dispatch(setRoom(room));
 
-        if (room) {
-            if (isUnsafeRoomWarningEnabled(getState()) && isInsecureRoomName(room)) {
-                navigateRoot(screen.unsafeRoomWarning);
+        if (!room) {
+            goBackToRoot(getState(), dispatch);
 
-                return;
-            }
-            dispatch(createDesiredLocalTracks());
-            dispatch(clearNotifications());
+            return;
+        }
 
-            const { hidePrejoin } = options;
+        dispatch(createDesiredLocalTracks());
+        dispatch(clearNotifications());
 
-            if (!hidePrejoin && isPrejoinPageEnabled(getState())) {
-                navigateRoot(screen.preJoin);
+        if (!options.hidePrejoin && isPrejoinPageEnabled(getState())) {
+            if (isUnsafeRoomWarningEnabled(getState()) && isInsecureRoomName(room)) {
+                navigateRoot(screen.unsafeRoomWarning);
             } else {
-                dispatch(connect());
-                navigateRoot(screen.conference.root);
+                navigateRoot(screen.preJoin);
             }
         } else {
-            goBackToRoot(getState(), dispatch);
+            dispatch(connect());
+            navigateRoot(screen.conference.root);
         }
     };
 }