Batched state changes are not flushed if the promise code changes the DOM (= attaching an iframe). Reproduceable with Safari.

React version: 18.1.0

## Steps To Reproduce

1. Open [codepen](https://codepen.io/kh-viewar/pen/wvpVLxM) with Safari.
2. Click "Upload"
3. => "Spinner" text does not render while Promise is in pending

Link to code example:

https://codepen.io/kh-viewar/pen/wvpVLxM

## The current behavior

State changes are not executed.

## The expected behavior

State should change to true and render spinner component. After promise is resolved (2 seconds timeout), state should switch back to false and spinner component should unmount.

## Original discussion

https://github.com/facebook/react/issues/24365
if (
      root.tag !== LegacyRoot &&
      isConcurrentActEnvironment() &&
      ReactCurrentActQueue.current === null
    ) {
      console.error(
        'A suspended resource finished loading inside a test, but the event ' +
          'was not wrapped in act(...).\n\n' +
          'When testing, code that resolves suspended data should be wrapped ' +
          'into act(...):\n\n' +
          'act(() => {\n' +
          '  /* finish loading suspended data */\n' +
          '});\n' +
          '/* assert on the output */\n\n' +
          "This ensures that you're testing the behavior the user would see " +
          'in the browser.' +
          ' Learn more at https:reactjs.org/link/wrap-tests-with-act',
      );
    }
  }
}
export function setIsRunningInsertionEffect(isRunning: boolean): void {
  if (__DEV__) {
    isRunningInsertionEffect = isRunning;
  }
}