Merge branch 'sh-fix-decomposition-spec' into 'master'

Fix broken CI job in single database mode

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/184396



Merged-by: Thong Kuah <tkuah@gitlab.com>
Approved-by: Thong Kuah <tkuah@gitlab.com>
Co-authored-by: Stan Hu <stanhu@gmail.com>

spec/keeps/overdue_finalize_background_migration_spec.rb

@@ -124,7 +124,7 @@
       let(:gitlab_schema) { 'gitlab_ci' }
 
       it 'returns the database name' do
-        expect(database_name).to eq('ci')
+        expect(database_name).to eq(database_exists?(:ci) ? 'ci' : 'main')
       end
     end
   end