[Fix] System only shows 20 attribute values while making variants (#13155)

diff --git a/erpnext/stock/doctype/item/item.js b/erpnext/stock/doctype/item/item.js
index 6993187..ff01a19 100644
--- a/erpnext/stock/doctype/item/item.js
+++ b/erpnext/stock/doctype/item/item.js
@@ -426,7 +426,9 @@
 						filters: [
 							["parent","=", attribute]
 						],
-						fields: ["attribute_value"]
+						fields: ["attribute_value"],
+						limit_start: 0,
+						limit_page_length: 500
 					}
 				}).then((r) => {
 					if(r.message) {