feat(waiting): add error handling for errors while waiting

[DomiR]

While using a custom cert pinnner calling completion(.failed(error)) will update the state with state waiting passing the cert error.

In this case we also should call the error handler.

[DomiR]

What do you think about this?

[daltoniam]

Makes sense, I like it. Going to cut another version (to fix some bugs) before merging this since it is a breaking changing with the enum case change. Thanks for the PR!

[scoreyou]

@daltoniam Are there any updates on this?