dataconnect: CHANGELOG.md: add link to #7314 for "Ignore unknown fields in response data" entry

Author: dconeybe

firebase-dataconnect/CHANGELOG.md

@@ -3,6 +3,7 @@
 - [changed] Ignore unknown fields in response data instead of throwing a
   `DataConnectOperationException` with message "decoding data from the server's response failed: An
   unknown field for index -3"
+  ([#7314](https://github.com/firebase/firebase-android-sdk/pull/7314))
 
 # 17.0.0