Fixes FOSS failure on api project spec

api/project_spec is failing on FOSS since 'issues_templates' and
'merge_requests_templates' attributes were moved to EE

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/323953

spec/requests/api/projects_spec.rb

@@ -1681,6 +1681,8 @@ RSpec.describe API::Projects do
             mirror
             requirements_enabled
             security_and_compliance_enabled
+            issues_template
+            merge_requests_template
           ]
         end