Fix Style/OpenStructUse offenses in project clusters_spec

Changelog: other

.rubocop_todo/style/open_struct_use.yml

@@ -16,7 +16,6 @@ Style/OpenStructUse:
   - spec/controllers/projects/clusters_controller_spec.rb
   - spec/factories/go_module_versions.rb
   - spec/factories/wiki_pages.rb
-  - spec/features/projects/clusters_spec.rb
   - spec/graphql/mutations/branches/create_spec.rb
   - spec/graphql/mutations/clusters/agent_tokens/create_spec.rb
   - spec/graphql/mutations/clusters/agents/create_spec.rb

spec/features/projects/clusters_spec.rb

@@ -99,7 +99,8 @@ RSpec.describe 'Clusters', :js do
 
         allow_any_instance_of(GoogleApi::CloudPlatform::Client)
           .to receive(:projects_zones_clusters_create) do
-          OpenStruct.new(
+          double(
+            'cluster_control',
             self_link: 'projects/gcp-project-12345/zones/us-central1-a/operations/ope-123',
             status: 'RUNNING'
           )