It’s hard to say. Both these snippets are from Google Documentation.
One of them is encouraging to move the the new platform while the other says that the identity toolkit related to Firebase will continue to be available until further notice.
I would say, as long as you keep an eye to see the notice enough time in advance you should be fine publishing the app with the example of @maptheunknown however you need to work in the migration to be ready to publish an update whenever required.