xwayland/glx: Mirror all EGLConfigs

Updated the for-loop that iterates over the received EGLConfigs to
include the very first EGLConfig with index 0.

Signed-off-by: Doğukan Korkmaztürk <dkorkmazturk@nvidia.com>
Fixes: 84692415 - xwayland: Add EGL-backed GLX provider