fix issue #16284, child table copy (#16285)

* fix issue #16284, child table copy 

V11 Child table from Clipboard Excel error, can't multiply sequence by non-int of type 'float'

* Update get_item_details.py

consider the empty string case

* Update get_item_details.py
diff --git a/erpnext/stock/get_item_details.py b/erpnext/stock/get_item_details.py
index 692fe5d..4910c42 100644
--- a/erpnext/stock/get_item_details.py
+++ b/erpnext/stock/get_item_details.py
@@ -252,8 +252,8 @@
 			item.get("taxes")))),
 		"uom": args.uom,
 		"min_order_qty": flt(item.min_order_qty) if args.doctype == "Material Request" else "",
-		"qty": args.qty or 1.0,
-		"stock_qty": args.qty or 1.0,
+		"qty": flt(args.qty) or 1.0,
+		"stock_qty": flt(args.qty) or 1.0,
 		"price_list_rate": 0.0,
 		"base_price_list_rate": 0.0,
 		"rate": 0.0,