[NEOS-920] Backend returning wrong authorization url to CLI when using internal url

[nickzelei]

When the backend is configured to use the internal url for the baseUrl, this causes the AuthorizationUrl to be returned to the CLI to be the internal.

It should instead return the frontend url, or the expected issuer.

The backend needs to be updated to return the correct value, otherwise the CLI cannot be used for login.

_{From SyncLinear.com | NEOS-920}

[nickzelei]

I've rolled back the backend to use the public url for now. Once this is fixed we can revert the backend to using the internal url.

[nickzelei]

See the comments in NEOS-1060 for more issues regarding internal/external urls.
Once we fix this, we can revert the admin api url back to using the internal URL as well.