fix displayName cc (#5536)

Author: dmceachernmsft

samples/Calling/src/app/views/HomeScreen.tsx

@@ -125,8 +125,7 @@ export const HomeScreen = (props: HomeScreenProps): JSX.Element => {
 
   registerIcons({ icons: { DialpadBackspace: <Backspace20Regular /> } });
   const isMobileSession = useIsMobile();
-  let showDisplayNameField = true;
-  showDisplayNameField = !teamsIdentityChosen;
+  const showDisplayNameField = !teamsIdentityChosen;
   const [teamsIdFormatError, setTeamsIdFormatError] = useState<boolean>(false);
 
   return (