fix(UX): list filter take zero as null (#25156) (#25221)

* fix: list filter take zero as null

* chore: fallback if null only

---------

Co-authored-by: Ankush Menat <ankushmenat@gmail.com>
(cherry picked from commit 7d7468c)

Co-authored-by: Kunhi <kunhimohamed6@gmail.com>

frappe/public/js/frappe/ui/filters/filter.js

@@ -418,7 +418,7 @@ frappe.ui.filter_utils = {
 	get_selected_value(field, condition) {
 		if (!field) return;
 
-		let val = field.get_value() || field.value;
+		let val = field.get_value() ?? field.value;
 
 		if (typeof val === "string") {
 			val = strip(val);