Fix environment deployment platform filter method / CE

Conflicts:
	lib/gitlab/prometheus/queries/query_additional_metrics.rb
	spec/models/environment_spec.rb

lib/gitlab/prometheus/queries/query_additional_metrics.rb

@@ -79,7 +79,7 @@ module Gitlab
         def common_query_context(environment, timeframe_start:, timeframe_end:)
           base_query_context(timeframe_start, timeframe_end).merge({
             ci_environment_slug: environment.slug,
-            kube_namespace: environment.project.deployment_platform(environment: environment)&.actual_namespace || '',
+            kube_namespace: environment.deployment_platform&.actual_namespace || '',
             environment_filter: %{container_name!="POD",environment="#{environment.slug}"}
           })
         end

spec/models/environment_spec.rb

@@ -375,8 +375,7 @@ describe Environment do
 
     context 'when there is a deployment platform for environment' do
       let!(:cluster) do
-        create(:cluster, :provided_by_gcp,
-               projects: [project])
+        create(:cluster, :provided_by_gcp, projects: [project])
       end
 
       it 'finds a deployment platform' do
@@ -389,6 +388,13 @@ describe Environment do
         expect(environment.deployment_platform).to be_nil
       end
     end
+
+    it 'checks deployment platforms associated with a project' do
+      expect(project).to receive(:deployment_platform)
+        .with(environment: environment.name)
+
+      environment.deployment_platform
+    end
   end
 
   describe '#terminals' do