build: fix meson warning for run_command

[matte-schwartz]

fixes:

WARNING: You should add the boolean check kwarg to the run_command call.
         It currently defaults to false,
         but it will default to true in future releases of meson.
         See also: https://github.com/mesonbuild/meson/issues/9300
Configuring GamescopeVersion.h using configuration

my bad 🐸 easy to miss while doing meson install -C build/ every time. definitely don't want this eventually failing builds compared to the original behavior.