Backspace gets stuck if held while hiding the keyboard

[fstachura]

To reproduce: hide the keyboard (for example, using the swipe down gesture) while holding the backspace key on the touchscreen keyboard. Activating any input box while the keyboard is hidden should cause the contents of the box to be deleted just like if the backspace key was actually held, same with any other keyboard-sensitive context.

Tested on maliitt keyboard (9b64784) and framework (8129694) master.
System info: Arch Linux, Plasma 6.0.2, Qt 6.6.2, Wayland.