ci: Fix the nick used in IRC reporting.

ci: Fix the nick used in IRC reporting.

robclark found that we needed unique IDs when multiple runners were trying
to report flakes at the same time, but it turns out due to nick limits (16
chars on freenode) we were just getting all the runners appended with
"-142" (or whatever the prefix of the pipelines are these days).  And, for
the new flake reporting from baremetal, all the runners ended up being
just "google-freedreno".

Reviewed-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4896>