operatorgroup: ensure clusterroleselectors in clusterrole aggregation rules are sorted

[joelanford]

Description of the change:

Ensure that selectors are always in sorted order when generating aggregation rules for operator group cluster roles.

Motivation for the change:

Lack of deterministic order of selectors in aggregation rules causes unnecessary updates of cluster roles, which can cause significant performance issues within the Kubernetes control plane.

Architectural changes:

None

Testing remarks:

Unit tests added to avoid regressions

Reviewer Checklist

• Implementation matches the proposed design, or proposal is updated to match implementation
• Sufficient unit test coverage
• Sufficient end-to-end test coverage
• Bug fixes are accompanied by regression test(s)
• e2e tests and flake fixes are accompanied evidence of flake testing, e.g. executing the test 100(0) times
• tech debt/todo is accompanied by issue link(s) in comments in the surrounding code
• Tests are comprehensible, e.g. Ginkgo DSL is being used appropriately
• Docs updated or added to /doc
• Commit messages sensible and descriptive
• Tests marked as [FLAKE] are truly flaky and have an issue
• Code is properly formatted