Allow clearing the buffer

[JoshSchreuder]

It would be nice to be able to clear the buffer as we may have duplicate requests, eg.

• Click the save button (which prompts for authentication)
• Cancel the resulting modal
• Click the save button again (prompting for authentication again)
• Login (actions both authentication requests)

[witoldsz]

authService has a loginCancelled(...) method. You should call it when user does not want to login, it will clear the buffer.

[JoshSchreuder]

Thanks @witoldsz, that's perfect.