Drop AuthorizeTypes offense in instance statistics

This MR fixes the Graphql/AuthorizeTypes by introducing a policy for the
instance statistics measurement model.

app/graphql/types/admin/analytics/instance_statistics/measurement_type.rb

 # frozen_string_literal: true
-# rubocop:disable Graphql/AuthorizeTypes
 
 module Types
   module Admin
     module Analytics
       module InstanceStatistics
         class MeasurementType < BaseObject
+          include Gitlab::Graphql::Authorize::AuthorizeResource
           graphql_name 'InstanceStatisticsMeasurement'
           description 'Represents a recorded measurement (object count) for the Admins'
 
+          authorize :read_instance_statistics_measurements
+
           field :recorded_at, Types::TimeType, null: true,
                 description: 'The time the measurement was recorded'
 

app/policies/analytics/instance_statistics/measurement_policy.rb

+# frozen_string_literal: true
+
+module Analytics
+  module InstanceStatistics
+    class MeasurementPolicy < BasePolicy
+      delegate { :global }
+    end
+  end
+end

app/policies/global_policy.rb

@@ -100,6 +100,7 @@ class GlobalPolicy < BasePolicy
     enable :update_custom_attribute
     enable :approve_user
     enable :reject_user
+    enable :read_instance_statistics_measurements
   end
 
   # We can't use `read_statistics` because the user may have different permissions for different projects

spec/graphql/types/admin/analytics/instance_statistics/measurement_type_spec.rb

@@ -8,4 +8,48 @@ RSpec.describe GitlabSchema.types['InstanceStatisticsMeasurement'] do
   it { is_expected.to have_graphql_field(:recorded_at) }
   it { is_expected.to have_graphql_field(:identifier) }
   it { is_expected.to have_graphql_field(:count) }
+
+  describe 'authorization' do
+    let_it_be(:measurement) { create(:instance_statistics_measurement, :project_count) }
+    let(:user) { create(:user) }
+
+    let(:query) do
+      <<~GRAPHQL
+        query instanceStatisticsMeasurements($identifier: MeasurementIdentifier!) {
+          instanceStatisticsMeasurements(identifier: $identifier) {
+            nodes {
+              count
+              identifier
+            }
+          }
+        }
+      GRAPHQL
+    end
+
+    subject do
+      GitlabSchema.execute(
+        query,
+        variables: { identifier: 'PROJECTS' },
+        context: { current_user: user }
+      ).to_h
+    end
+
+    context 'when the user is not admin' do
+      it 'returns no data' do
+        expect(subject.dig('data', 'instanceStatisticsMeasurements')).to be_nil
+      end
+    end
+
+    context 'when user is an admin' do
+      let(:user) { create(:user, :admin) }
+
+      before do
+        stub_feature_flags(user_mode_in_session: false)
+      end
+
+      it 'returns data' do
+        expect(subject.dig('data', 'instanceStatisticsMeasurements', 'nodes')).not_to be_empty
+      end
+    end
+  end
 end