Notifications Menu is displayed on the first open shifted to the right out of view on smaller mobile screens

Steps to reproduce

1. Open the XWiki instance on a smaller mobile screen viewport (e.g. 360 x 740 or 412 x 915 - Samsung Galaxy S20 Ultra)
2. Login
3. Click on the Notifications bell
4. Observe the placement of the Notifications Menu

Expected results

The Notifications Menu is placed within the screen's viewport.

Actual results

The Notifications Menu is displayed shifted out of the viewport, on the right.

However, if the menu is closed (by clicking elsewhere) and opened again, it's displayed properly within the viewport, until the page is refreshed.

Tested and reproduced also on XWiki 15.10.8 and 16.2.0.