fix(native-filters): empty label indicator (#15084)

superset-frontend/src/filters/components/Select/SelectFilterPlugin.test.tsx

@@ -150,7 +150,7 @@ describe('SelectFilterPlugin', () => {
         ],
       },
       filterState: {
-        label: '',
+        label: undefined,
         value: null,
       },
     });
@@ -165,7 +165,7 @@ describe('SelectFilterPlugin', () => {
       },
       extraFormData: {},
       filterState: {
-        label: '',
+        label: undefined,
         value: null,
       },
     });

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

@@ -138,7 +138,9 @@ export default function PluginFilterSelect(props: PluginFilterSelectProps) {
           inverseSelection,
         ),
         filterState: {
-          label: `${(values || []).join(', ')}${suffix}`,
+          label: values?.length
+            ? `${(values || []).join(', ')}${suffix}`
+            : undefined,
           value:
             appSection === AppSection.FILTER_CONFIG_MODAL && defaultToFirstItem
               ? undefined