ci: Adapt armhf_test job to MESA_TEMPLATES_COMMIT related changes

I missed this before somehow.

Fixes: 0781d9825b31 "ci: Append $MESA_TEMPLATES_COMMIT to image tags"
Reviewed-by: Andres Gomez <agomez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7957>
1 file changed