Fix misplaced waitForPendingWrites (#3654)
Fix misplaced waitForPendingWrites (#3654)

* Fix misplaced waitForPendingWrites

* reformat

firebase/firebase-ios-sdk,firebase/firebase-ios-sdk,firebase/firebase-ios-sdk,firebase/firebase-ios-sdk,firebase/firebase-ios-sdk,firebase/firebase-ios-sdk,firebase/firebase-ios-sdk