<!-- WARNING: Prior to submitting an enhancement request, we ask that you create a discussion. If you have not yet created a discussion related to your request, please do so now: https://github.com/nginx/nginx-gateway-fabric/discussions/new?category=ideas --> ### Overview As a user of NGF, I would like to add CEL tests for the AuthenticationFilter CR so that I can be confident that the CEL validation works as I expect ### Acceptance ... (todo) <!-- NOTE: depending on the scope of the enhancement, you may be asked to use the Enhancement Proposal process to document your work: https://github.com/nginx/nginx-gateway-fabric/blob/main/eps/README.md -->