Some recurrent messages are only cluttering the ci_run_n_monitor's logs, so let's use the easily provided @cache decorator to print stuff that the user will only needs to see once. Also removes some junk that can happen during the pipeline monitoring loop, like the "----" line break, and newlines. Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30361>