Fix compile

Author: schmidt-sebastian

packages/firestore/exp/src/api/reference.ts

@@ -265,15 +265,15 @@ export function addDoc<T>(
   const firestore = cast(collRef.firestore, Firestore);
   const docRef = doc(collRef);
 
-  const convertedValue = applyFirestoreDataConverter(collRef._converter, data);
+  const convertedValue = applyFirestoreDataConverter(collRef.converter, data);
 
   const dataReader = newUserDataReader(collRef.firestore);
   const parsed = parseSetData(
     dataReader,
     'addDoc',
     docRef._key,
     convertedValue,
-    collRef._converter !== null,
+    collRef.converter !== null,
     {}
   );