fix: avoid exception by possible undefined event

src/logic/createFormControl.ts

@@ -680,7 +680,11 @@ export function createFormControl<
   };
 
   const onChange: ChangeHandler = async (event) => {
+    if (!event) {
+      return;
+    }
     _state.mount = true;
+
     const target = event.target;
     let name = target.name as string;
     let isFieldValueUpdated = true;