x11-wm/gamescope: temporarily disable wayland category

$ gamescope -- vkcube-wayland
No CAP_SYS_NICE, falling back to regular-priority compute and threads.
Performance will be affected.
wlserver: [backend/headless/backend.c:68] Creating headless backend
vulkan: selecting physical device 'Intel(R) HD Graphics 530 (SKL GT2)': queue family 0
vulkan: physical device supports DRM format modifiers
vulkan: supported DRM formats for sampling usage:
vulkan: 0x34325241
vulkan: 0x34325258
vulkan: 0x3231564E
wlserver: Running compositor on wayland display 'gamescope-0'
wlserver: [backend/headless/backend.c:16] Starting headless backend
wlserver: [xwayland/server.c:108] Starting Xwayland on :1
wlserver: [types/wlr_compositor.c:681] New wlr_surface 0x84aae6500 (res 0x84ab47880)
wlserver: [xwayland/server.c:273] Xserver is ready
xwm: Failed to find PID for window 0x200001
Cannot connect to wayland.
Exiting ...
load: 0.97 cmd: Xwayland 64175 [select] 8.23r 0.02u 0.00s 0% 35848k
^C
gamescope: received kill signal, terminating!