#7576 correct link to admin services in swagger API ref

[planetf1]

Description

Corrects link in the swagger API reference for admin services to point to the docs at https://egeria-project.org/services/admin-services/overview

Related Issue(s)

Fixes #7576

Testing

Release Notes & Documentation

Additional notes

[mandy-chessell]

The link should be https://egeria-project.org/guides/operations/overview/#operating-an-omag-server

[planetf1]

The link should be egeria-project.org/guides/operations/overview/#operating-an-omag-server

I did look at that page too, as it was also a good candidate, but decided to propose the services reference as it felt closer to the reference nature of the API docs. Of course concepts are crucial too, but they were linked in the document I targetted in any case.

Many of our other URL links in swagger currently also point to services
I'll update the PR with the ops guide instead.