Clean up the agentgateway plugin definitions to reuse kclient between plugin and Status, because they are clients for the same API resource.

Examples:

• https://github.com/kgateway-dev/kgateway/blob/main/pkg/agentgateway/plugins/traffic_plugin.go#L85C32-L85C50

• kgateway/internal/kgateway/extensions2/plugins/directresponse/direct_response_plugin.go

  Line 49 in 11221e1

  col := krt.WrapClient(kclient.NewFilteredDelayed[*v1alpha1.DirectResponse](

This is similar to the pattern we use in the envoy plugins:

	return sdk.Plugin{
		ContributesPolicies: map[schema.GroupKind]sdk.PolicyPlugin{
			wellknown.TrafficPolicyGVK.GroupKind(): {
                                ....
				GetPolicyStatus:   getPolicyStatusFn(cli),
				PatchPolicyStatus: patchPolicyStatusFn(cli),
			},
		},