fix: close platform access re-review findings

frontend/platform_admin/scripts/final-important.test.mjs

@@ -172,3 +172,21 @@ test('platform role UI replaces assigned menu identities through the singular co
   assert.match(platformApi, /\/platform\/platform_role\/\$\{identity\}\/menu/);
   assert.match(platformApi, /method:\s*['"]PUT['"]/);
 });
+
+test('platform role UI permits an empty menu selection to revoke every assignment', () => {
+  const resources = loadResources();
+  const { buildResourcePayload, isMissingField } = loadResourceForm();
+  const role = resources.find((item) => item.name === 'platform_role');
+  const menuField = role.detailActions
+    .flatMap((action) => action.fields)
+    .find((field) => field.key === 'menu_identities');
+
+  assert.equal(menuField.required, undefined);
+  assert.equal(isMissingField([]), true);
+  assert.deepEqual(
+    JSON.parse(JSON.stringify(buildResourcePayload([menuField], {
+      menu_identities: [],
+    }))),
+    { menu_identities: [] },
+  );
+});