Revert "fix(iOS): unify prefetchImageWithMetadata's signature in JS and ObjC land (facebook#47532)"

This reverts commit 4dd60ac.

Author: rezkiy37

packages/react-native/Libraries/Image/RCTImageLoader.mm

@@ -1227,7 +1227,7 @@ - (void)cancelRequest:(id)requestToken
 
 RCT_EXPORT_METHOD(prefetchImageWithMetadata
                   : (NSString *)uri queryRootName
-                  : (nullable NSString *)queryRootName rootTag
+                  : (NSString *)queryRootName rootTag
                   : (double)rootTag resolve
                   : (RCTPromiseResolveBlock)resolve reject
                   : (RCTPromiseRejectBlock)reject)