[docs]The transparent mask does not disappear

**Describe the bug**
When I access https://day.js.org/, I can't click on the page, I found the transparent mask(id="exConfirmPromiseOverLay") does not disappear.

**Expected behavior**
The transparent mask disappears

**Information**
- Day.js Version [e.g. v1.0.0]
- OS: [e.g. iOS]
- Browser [e.g. Firefox Quantum 62]
- Time zone: [e.g. GMT-07:00 DST (Pacific Daylight Time)]

Open https://day.js.org/ and reproduce the blocked page interaction. Inspect the transparent mask with id="exConfirmPromiseOverLay" and trace why it remains visible; done means the mask disappears and the page can be clicked normally.

Written by the indexing model from the issue text.