Merge branch 'mo-remove-decompose-namespace-monthly-usage' into 'master'

Remove ci_decompose_for_namespace_monthly_usage_query feature flag

See merge request gitlab-org/gitlab!79004

config/feature_flags/development/ci_decompose_for_namespace_monthly_usage_query.yml

----
-name: ci_decompose_for_namespace_monthly_usage_query
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/77952
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/350146
-milestone: '14.7'
-type: development
-group: group::pipeline execution
-default_enabled: false

ee/app/models/ci/minutes/project_monthly_usage.rb

@@ -12,17 +12,10 @@ module Ci
       scope :current_month, -> { where(date: beginning_of_month) }
 
       scope :for_namespace_monthly_usage, -> (namespace_monthly_usage) do
-        if Feature.enabled?(:ci_decompose_for_namespace_monthly_usage_query, namespace_monthly_usage.namespace, default_enabled: :yaml)
         where(
           date: namespace_monthly_usage.date,
           project: Ci::ProjectMirror.by_namespace_id(namespace_monthly_usage.namespace_id).select(:project_id)
         )
-        else
-          where(
-            date: namespace_monthly_usage.date,
-            project: namespace_monthly_usage.namespace.projects
-          ).allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/343301')
-        end
       end
 
       def self.beginning_of_month(time = Time.current)

ee/spec/models/ci/minutes/project_monthly_usage_spec.rb

@@ -77,7 +77,6 @@ RSpec.describe Ci::Minutes::ProjectMonthlyUsage do
   end
 
   describe '.for_namespace_monthly_usage' do
-    shared_examples 'namespace monthly usage' do
     let(:date_for_usage) { Date.new(2021, 5, 1) }
     let(:namespace_usage) { create(:ci_namespace_monthly_usage, namespace: project.namespace, amount_used: 50, date: date_for_usage) }
 
@@ -99,19 +98,6 @@ RSpec.describe Ci::Minutes::ProjectMonthlyUsage do
     end
   end
 
-    context 'when ci_decompose_for_namespace_monthly_usage_query is enabled' do
-      it_behaves_like 'namespace monthly usage'
-    end
-
-    context 'when ci_decompose_for_namespace_monthly_usage_query is disabled' do
-      before do
-        stub_feature_flags(ci_decompose_for_namespace_monthly_usage_query: false)
-      end
-
-      it_behaves_like 'namespace monthly usage'
-    end
-  end
-
   context 'loose foreign key on ci_project_monthly_usages.project_id' do
     it_behaves_like 'cleanup by a loose foreign key' do
       let!(:parent) { create(:project) }