tablet pen does not work well when using shift and the grp:shifts_toggle option is active.

[MirkoHernandez]

sway version 1.8.1

Steps to reproduce the problem

1. Set xkb_options to "grp:shifts_toggle"
2. Press shift and then use the pen to select something.
3. Lifting shift and the pen does keep shift active.

This problem can be seen when selecting text (any application) or in applications like Krita (changing the brush).

Using other option like grp:alt_caps_toggle solves the issue.