authData is not cleaned up when linkWithAsync() fails

[mhartvick]

Whenever linkWithAsync() fails, the anonymity is restored, but the authData map still contains the value for the authType that just failed.

It's unexpected from a consumer point of view, isLinked(myAuthType) will be true right after failing to link the exact same myAuthType, and differs from the iOS behavior (according to a colleague of mine who tried to reproduce the issue on its platform)

[flovilmart]

@rogerhu can you have a look please?
@mhartvick could you come up with a failing test and a fix?

[Jawnnypoo]

Seems like we can close this out now. Thanks for the contribution @mhartvick !