Fix indices.delete_api response

Author: pquentin

output/openapi/elasticsearch-openapi.json

@@ -47,6 +47,7 @@ export class WriteResponseBase {
 export class AcknowledgedResponseBase {
   /** For a successful response, this value is always true. On failure, an exception is returned instead. */
   acknowledged: boolean
+  errors?: boolean
 }
 
 export class DynamicResponseBase {}