Exclude generic codeowners rule

What does this MR do and why?

Exclude generic codeowners rule because it's confusing to show it in roulette and it's not needed because it's already covered by other rules.

See this merge request for why we added this generic rule which we can ignore here: gitlab-org/gitlab!96696 (merged)

Context: Internal Slack thread

Example merge request showing this: gitlab-org/gitlab!95366 (merged)

It was from this generic codeowners rule:

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.