fix(misc) fix typeof comparison to undefined

modules/API/external/external_api.js

 
     switch (typeof firstArg) {
     case 'string': // old arguments format
-    case undefined: {
+    case 'undefined': {
         // Not sure which format but we are trying to parse the old
         // format because if the new format is used everything will be undefined
         // anyway.

react/features/mobile/watchos/middleware.js

 
         switch (command) {
         case CMD_HANG_UP:
-            if (typeof getCurrentConferenceUrl(getState()) !== undefined) {
+            if (typeof getCurrentConferenceUrl(getState()) !== 'undefined') {
                 dispatch(appNavigate(undefined));
             }
             break;