FirebaseCacheManager uses DownloadUrl which has a token in the url defeating cache

[FirebaseCacheManager](https://github.com/Baseflow/flutter_cache_manager/blob/develop/flutter_cache_manager_firebase/lib/src/firebase_http_file_service.dart#L36) uses the `ref.getDownloadUrl()` which typically returns a url with a dynamic access token in the query string of the URL. Doesn't that mostly defeat the purpose of the cache, assuming that the key of the file in the cache is tho whole url including the token?