Allow OAuth flow to happen in external browser to support Okta/YubiKey

[Helge Heß]

A request coming in by email:

I’m trying to sign into a Slack workspace that uses Okta, but our particular Okta configuration requires use of a YubiKey, which doesn’t work inside of your web view. Can you offer a way to do the login flow so that it works through the browser instead of the in-app browser?

I think that should be possible.