Update tips_and_troubleshooting.md to document issue with registry/config.yml

What does this Merge Request do?

I've run into this problem where the wrong url is in a config file for the registry a few times so I figured I would at least document it.

I first ran into it during onboarding and it stumped me but seemed to eventually resolve itself.

This is probably a gdk bug.

Merge Request checklist

• [-] Tests added for new functionality. If not, please raise Issue to follow-up.
• [-] This change is backward compatible. If not, please include steps to communicate to our users.
• Documentation added/updated, if needed.
• [-] gdk doctor test added, if needed.