virgl/ci: disable virgl-traces because it doesn't upload results

Not being able to review results makes it impossible to update the hashes.

Suggested by Daniel Stone.

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31942>
1 file changed