Adam from Google said in a Google Webmaster Help thread that Google's Firebase App Indexing now added Bitcode support for iOS Apps. He wrote, "Update: Bitcode support is now available."
The iOS release notes adds that this is a new feature "Bitcode support is now available for the App Indexing SDK for iOS."
The thing is, I thought this was added back on March 10th or maybe that was a developer beta release? I am not sure.
In any event, this solves some issues for iOS developers trying to implement App Indexing on some apps.
Forum discussion at Google Webmaster Help.