Hide DatabaseSwift for M92. (#7727)
Hide DatabaseSwift for M92. (#7727)

* Hide DatabaseSwift for M92.

This still needs to go through API review before being published.

* Fix TODO indentation

* Spelling
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