fix: the JSON object must be str, bytes or bytearray, not "list" (#23047)

Co-authored-by: Rucha Mahabal <ruchamahabal2@gmail.com>
diff --git a/erpnext/accounts/doctype/bank_guarantee/bank_guarantee.py b/erpnext/accounts/doctype/bank_guarantee/bank_guarantee.py
index f28a074..88e1055 100644
--- a/erpnext/accounts/doctype/bank_guarantee/bank_guarantee.py
+++ b/erpnext/accounts/doctype/bank_guarantee/bank_guarantee.py
@@ -27,4 +27,4 @@
 	for col in column_list:
 		sanitize_searchfield(col) 
 	return frappe.db.sql(''' select {columns} from `tab{doctype}` where name=%s'''
-		.format(columns=", ".join(json.loads(column_list)), doctype=doctype), docname, as_dict=1)[0]
+		.format(columns=", ".join(column_list), doctype=doctype), docname, as_dict=1)[0]