Merge branch 'sk/339028-fix-policy-yaml-response' into 'master'

Stringify policy yaml response in scanExecutionPolicies graphql query

See merge request gitlab-org/gitlab!68656

ee/app/graphql/resolvers/scan_execution_policy_resolver.rb

@@ -19,7 +19,7 @@ def resolve(**args)
           name: policy[:name],
           description: policy[:description],
           enabled: policy[:enabled],
-          yaml: policy.to_yaml,
+          yaml: YAML.dump(policy.deep_stringify_keys),
           updated_at: policy_configuration.policy_last_updated_at
         }
       end

ee/spec/graphql/resolvers/scan_execution_policy_resolver_spec.rb

@@ -57,7 +57,7 @@
             name: 'Run DAST in every pipeline',
             description: 'This policy enforces to run DAST for every pipeline within the project',
             enabled: true,
-            yaml: policy.to_yaml,
+            yaml: YAML.dump(policy.deep_stringify_keys),
             updated_at: policy_last_updated_at
           }
         ]