Memoize the code owners file after loading

MR: gitlab.com/gitlab-org/gitlab/-/merge_requests/60980

ee/lib/gitlab/code_owners/loader.rb

@@ -62,11 +62,7 @@ module Gitlab
       end
 
       def code_owners_file
-        if RequestStore.active?
-          RequestStore.fetch("project-#{@project.id}:code-owners:#{@ref}") do
-            load_code_owners_file
-          end
-        else
+        @code_owners_file ||= Gitlab::SafeRequestStore.fetch("project-#{@project.id}:code-owners:#{@ref}") do
           load_code_owners_file
         end
       end

ee/spec/lib/gitlab/code_owners/loader_spec.rb

@@ -43,6 +43,12 @@ RSpec.describe Gitlab::CodeOwners::Loader do
       expect(loader.entries).to contain_exactly(expected_entry)
     end
 
+    it 'only calls out to the repository once' do
+      expect(project.repository).to receive(:code_owners_blob).once
+
+      2.times { loader.entries }
+    end
+
     it 'loads all users that are members of the project into the entry' do
       expect(first_entry.users).to contain_exactly(owner_1, email_owner, documentation_owner)
     end