Avoid hotloop over empty clusterrole rules

[akalenyu]

What this PR does / why we need it:
For an empty list, we get in a hotloop over it being persisted with nil

2026-01-14T04:29:20Z	INFO	DIFF	{"controller": "migcontroller-controller", "object": {"name":"migcontroller-kubevirt-hyperconverged","namespace":"openshift-cnv"}, "namespace": "openshift-cnv", "name": "migcontroller-kubevirt-hyperconverged", "reconcileID": "d5cabc29-c944-4271-8b88-b5284c55c266", "obj": {"apiVersion": "rbac.authorization.k8s.io/v1", "kind": "ClusterRole", "name": "migrations.kubevirt.io:admin"}, "patch": "[{\"op\":\"add\",\"path\":\"/rules\",\"value\":[]}]"}

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Checklist

This checklist is not enforcing, but it's a reminder of items that could be relevant to every PR.
Approvers are expected to review this list.

• Design: A design document was considered and is present (link) or not required
• PR: The PR description is expressive enough and will help future contributors
• Code: Write code that humans can understand and Keep it simple
• Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
• Upgrade: Impact of this change on upgrade flows was considered and addressed if required
• Testing: New code requires new unit tests. New features and bug fixes require at least on e2e test
• Documentation: A user-guide update was considered and is present (link) or not required. You want a user-guide update if it's a user facing feature / API change.
• Community: Announcement to kubevirt-dev was considered

Release note:

BugFix: event spam over rbac update

[maiqueb]

tks

[kubevirt-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: akalenyu, maiqueb

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[kubevirt-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[kubevirt-bot]

There has been no activity on this PR for 59 days and it has been stale for 14 days.
To protect limited CI resources, it has been automatically labelled 'rotten' and will be closed in 7 days.

What you can do:

• If the PR is waiting on you to respond to a question or feedback and/or update the PR, please do so.
• You can mark the PR as fresh and remove the label with the following command: /remove-lifecycle rotten
• If this PR is safe to close now, please help the project by closing it with: /close
• If you need attention on this PR from a reviewer, you can raise it on the agenda of the relevant SIG meeting or KubeVirt Community meeting, or ping the kubevirt-dev slack channel.

/lifecycle rotten