Fix namespace ambiguity with Kubernetes Pod definitions

This was causing a spec failure between Gitlab::Kubernetes::Helm::Pod and
Gitlab::Kubernetes::Helm::Api::Pod if one spec loaded the former
definition first.

Closes #41458

lib/gitlab/kubernetes/helm/api.rb

@@ -34,7 +34,7 @@ module Gitlab
         private
 
         def pod_resource(command)
-          Pod.new(command, @namespace.name, @kubeclient).generate
+          Gitlab::Kubernetes::Helm::Pod.new(command, @namespace.name, @kubeclient).generate
         end
       end
     end