Opening a file via legacy-API throws AbortError

[dwelle]

Steps:

1. in Firefox, open a file that has no extension
2. instead of resolving with the Blob, it throws AbortError

sandbox: https://srzn8.csb.app/

(via excalidraw/excalidraw#3155)

Introduced in 5d8a551

[dwelle]

Can be hack-fixed by running the cancelDetector in a next tick, but I'd still be hesitant to call it a surefire solution:

const cancelDetector = () => {
  window.removeEventListener('focus', cancelDetector);
  requestAnimationFrame(() => {
    requestAnimationFrame(() => {
      if (input.files.length === 0) {
        reject(
          new DOMException('The user aborted a request.', 'AbortError')
        );
      }
    });
  });
};