Changes to POST /api/graphql/integrations

added the optional property reason to the response with the 403 status

added the non-success response with the status 403

added the optional property retryable to the response with the 500 status

added the new invalid-endpoint enum value to the anyOf[#/components/schemas/GraphqlIntrospectionError]/reason/anyOf[subschema #1] response property for the response status 400