fix(operator): broken CiliumEndpoint garbage collection (#801)

# Description

Retina Operator deletes endpoints when processing Pod delete events, but
if for some reason an endpoint exists after its Pod was deleted, then
endpoint GC comes into play.

Endpoint GC was broken because it was failing to watch CiliumNodes. Fix
by using a fake CiliumNodes resource.

## Related Issue

Fixes #598 (logs and details there)

## Checklist

- [x] I have read the [contributing
documentation](https://retina.sh/docs/contributing).
- [x] I signed and signed-off the commits (`git commit -S -s ...`). See
[this
documentation](https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification)
on signing commits.
- [x] I have correctly attributed the author(s) of the code.
- [x] I have tested the changes locally.
- [x] I have followed the project's style guidelines.
- [ ] I have updated the documentation, if necessary.
- [ ] I have added tests, if applicable.

## Testing Completed

Manual testing. Operator e2e's are WIP in another PR.

Signed-off-by: Hunter Gregory <[email protected]>

Author: huntergregory

operator/cilium-crds/k8s/fakeresource.go

@@ -0,0 +1,23 @@
+package k8s
+
+import (
+	"context"
+
+	k8sRuntime "k8s.io/apimachinery/pkg/runtime"
+
+	"github.com/cilium/cilium/pkg/k8s/resource"
+)
+
+type fakeresource[T k8sRuntime.Object] struct {
+}
+
+func (f *fakeresource[T]) Events(ctx context.Context, opts ...resource.EventsOpt) <-chan resource.Event[T] {
+	return make(<-chan resource.Event[T])
+}
+
+func (f *fakeresource[T]) Store(ctx context.Context) (resource.Store[T], error) {
+	return nil, nil
+}
+
+func (f *fakeresource[T]) Observe(ctx context.Context, next func(resource.Event[T]), complete func(error)) {
+}

operator/cilium-crds/k8s/resources.go

@@ -36,7 +36,9 @@ var ResourcesCell = cell.Module(
 		k8s.CiliumIdentityResource,
 		CiliumEndpointResource,
 		CiliumEndpointSliceResource,
-		k8s.CiliumNodeResource,
+		func() resource.Resource[*cilium_api_v2.CiliumNode] {
+			return &fakeresource[*cilium_api_v2.CiliumNode]{}
+		},
 		k8s.PodResource,
 		k8s.NamespaceResource,
 	),