fix: TypeError is pricing rules (backport #39252) (#39259)

fix: TypeError is pricing rules (#39252)

(cherry picked from commit 274c65c451)

Co-authored-by: rohitwaghchaure <rohitw1991@gmail.com>

erpnext/accounts/doctype/pricing_rule/utils.py

@@ -521,7 +521,7 @@ def get_qty_amount_data_for_cumulative(pr_doc, doc, items=None):
 		values.extend(warehouses)
 
 	if items:
-		condition = " and `tab{child_doc}`.{apply_on} in ({items})".format(
+		condition += " and `tab{child_doc}`.{apply_on} in ({items})".format(
 			child_doc=child_doctype, apply_on=apply_on, items=",".join(["%s"] * len(items))
 		)