[Bug fix] Can't modify a custom filter without label (#59296) (#59324)

* Show filter value if nothing else is available for label value

* Add label max width

* Revert "Add label max width"

This reverts commit 9537968110.

src/plugins/data/public/ui/filter_bar/filter_editor/lib/filter_label.tsx

@@ -98,7 +98,7 @@ export function FilterLabel({ filter, valueLabel }: Props) {
       return (
         <Fragment>
           {prefix}
-          {JSON.stringify(filter.query)}
+          {JSON.stringify(filter.query) || filter.meta.value}
         </Fragment>
       );
   }