Refactor subscribeToKey function in OnyxUtils to improve code clarity by removing unnecessary comments and unused code related to provisional mapping cleanup.

Author: pasyukevich

lib/OnyxUtils.ts

@@ -1081,10 +1081,8 @@ function subscribeToKey<TKey extends OnyxKey>(connectOptions: ConnectOptions<TKe
         if (skippableIDs.size) {
             const [, collectionMemberID] = OnyxKeys.splitCollectionMemberKey(mapping.key);
             if (skippableIDs.has(collectionMemberID)) {
-                // Clean up the provisional mapping to avoid retaining unused subscribers
-                // Mark this key as known-nullish and present in cache so hooks see a loaded undefined state
+                // Clean up the provisional mapping to avoid retaining unused subscribers.
                 cache.addNullishStorageKey(mapping.key);
-                cache.set(mapping.key, undefined as OnyxValue<TKey>);
                 delete callbackToStateMapping[subscriptionID];
                 return subscriptionID;
             }