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
setCurrentUpdatePriority(previousPriority);
    ReactCurrentBatchConfig.transition = prevTransition;
    if (executionContext === NoContext) {
      resetRenderTimer();
    }
  }
}
 Overload the definition to the two valid signatures.
 Warning, this opts-out of checking the function body.
declare function flushSync<R>(fn: () => R): R;
 eslint-disable-next-line no-redeclare
declare function flushSync(): void;
 eslint-disable-next-line no-redeclare
export function flushSync(fn) {
   
   
  if (
    rootWithPendingPassiveEffects !== null &&
    rootWithPendingPassiveEffects.tag === LegacyRoot &&
    (executionContext & (RenderContext | CommitContext)) === NoContext
  ) {
    flushPassiveEffects();
  }
  const prevExecutionContext = executionContext;
  executionContext |= BatchedContext;
  const prevTransition = ReactCurrentBatchConfig.transition;
  const previousPriority = getCurrentUpdatePriority();
  try {
    ReactCurrentBatchConfig.transition = null;
    setCurrentUpdatePriority(DiscreteEventPriority);