Fix authentication URL port handling

[maci3jka]

When the cluster URL includes a non-default port (non 443) and the verification URL does not specify one, the browser was opened to the wrong host — missing the port entirely and causing the authentication flow to fail.
Example that I faced when port forwarding k8s service

$engflow_auth login --insecure localhost:8443
Warning: server TLS validation is disabled
Attempting to automaticaly open the authentication URL in your web browser.
If the browser does not open or you wish to use a different device to authorize this request, open the following URL:

        https://localhost/login?userCode=XXXX-YYYY-ZZZZ&redirect=QWERTY123==

[laszlocsomor]

Please rebase; CI should pass at f1ab63d

[maci3jka]

Please rebase; CI should pass at f1ab63d

@laszlocsomor done

[laszlocsomor]

And please describe in the PR message what was the bug. Looks like when the cluster listens on a nonstandard port, the verification URL should contain it too, but please confirm.

When would this be a problem, I mean in what case do you access a cluster on a nonstandard port?

[maci3jka]

I've faced

$engflow_auth login --insecure localhost:8443
Warning: server TLS validation is disabled
Attempting to automaticaly open the authentication URL in your web browser.
If the browser does not open or you wish to use a different device to authorize this request, open the following URL:

        https://localhost/login?userCode=XXXX-YYYY-ZZZZ&redirect=QWERTY123==

this pr fixes that. I've updated the description

[jayconrod]

Hi @maci3jka, for legal reasons, we don't accept external PRs in this repo. We haven't got a contributor license agreement or copyright assignment in place. (And CI is failing because the required secret is not exposed for external PRs).

Could you tell us more what you're trying to do? I can confirm engflow_auth login works on a local port for a cluster running locally. But it sounds like you might be authenticating through a local proxy running against another EngFlow server, and you want to rewrite the verification URL specified by the server to use the local proxy port instead of the remote port. Is that right?