Cleanup store_ci_pipeline_counts_by_status FF

This change removes the store_ci_pipeline_counts_by_status
feature flag.

app/models/analytics/instance_statistics/measurement.rb

@@ -38,11 +38,7 @@ module Analytics
       scope :with_identifier, -> (identifier) { where(identifier: identifier) }
 
       def self.measurement_identifier_values
-        if Feature.enabled?(:store_ci_pipeline_counts_by_status, default_enabled: true)
         identifiers.values
-        else
-          identifiers.values - EXPERIMENTAL_IDENTIFIERS.map { |identifier| identifiers[identifier] }
-        end
       end
     end
   end

config/feature_flags/development/store_ci_pipeline_counts_by_status.yml

----
-name: store_ci_pipeline_counts_by_status
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/43027
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/254721
-type: development
-group: group::analytics
-default_enabled: true

spec/models/analytics/instance_statistics/measurement_spec.rb

@@ -48,26 +48,10 @@ RSpec.describe Analytics::InstanceStatistics::Measurement, type: :model do
   end
 
   describe '#measurement_identifier_values' do
-    subject { described_class.measurement_identifier_values.count }
-
-    context 'when the `store_ci_pipeline_counts_by_status` feature flag is off' do
-      let(:expected_count) { Analytics::InstanceStatistics::Measurement.identifiers.size - Analytics::InstanceStatistics::Measurement::EXPERIMENTAL_IDENTIFIERS.size }
-
-      before do
-        stub_feature_flags(store_ci_pipeline_counts_by_status: false)
-      end
-
-      it { is_expected.to eq(expected_count) }
-    end
-
-    context 'when the `store_ci_pipeline_counts_by_status` feature flag is on' do
     let(:expected_count) { Analytics::InstanceStatistics::Measurement.identifiers.size }
 
-      before do
-        stub_feature_flags(store_ci_pipeline_counts_by_status: true)
-      end
+    subject { described_class.measurement_identifier_values.count }
 
     it { is_expected.to eq(expected_count) }
   end
-  end
 end