[REG 6.3 -> 6.4] Rendering stops without user input with sway/wlroots

With Qt 6.4, when running simplebrowser under e.g. sway and visiting time.is, the time display only updates while e.g. typing something into the window, or moving the mouse pointer. When no input is provided, rendering stops and the page content isn't updated.

This can be reproduced even when launching Sway as a window under X11, and it can be reproduced with other Wayland compositors using wlroots, e.g. qtile when running with qtile start -b wayland. However, Weston is not affected.

Qt 6.3 works fine, this only started happening with Qt 6.4.

Downstream issue: https://github.com/qutebrowser/qutebrowser/issues/7532