refactor LegacyCMS componnet: set default affix and adjust step completion logic and removed checks for affix

Author: yashin4112

ui/src/components/LegacyCms/Actions/LoadPrefix.tsx

@@ -29,6 +29,7 @@ const LoadPreFix = (props: LoadSelectCmsProps) => {
 
   const dispatch = useDispatch();
 
+  const [prefix, setPrefix] = useState<string>(newMigrationData?.legacy_cms?.affix || 'cs');
   const [prefix, setPrefix] = useState<string>(newMigrationData?.legacy_cms?.affix || 'cs');
 
   const [isError, setIsError] = useState<boolean>(false);