fix(native-filters): set currentValue null when empty (#13000)

superset-frontend/src/dashboard/components/nativeFilters/FilterBar/CascadePopover.tsx

@@ -108,7 +108,7 @@ const CascadePopover: React.FC<CascadePopoverProps> = ({
         return activeChildren;
       }
 
-      if (currentValue) {
+      if (currentValue !== undefined && currentValue !== null) {
         return [filter];
       }
 

superset-frontend/src/filters/components/Select/AntdSelectFilter.tsx

@@ -74,7 +74,7 @@ export default function AntdPluginFilterSelect(
         inverseSelection,
       ),
       currentState: {
-        value: resultValue,
+        value: resultValue.length ? resultValue : null,
       },
     });
   };