Exempt group hooks from being disabled

What does this MR do and why?

This is a temporary measure until we have notifications for group hooks.

See: #385902 (closed)

How to set up and validate locally

Example below:

1. Set up a web-hook for a group.
2. Trigger the web-hook, see that the events are delivered.
3. Cause the web-hook receiver to fail (either 5xx or 4xx ranges)
4. Trigger the web-hook, see that the events are delivered.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.