ci/bare-metal: Use re.search() instead re.match() for our line matching.

ci/bare-metal: Use re.search() instead re.match() for our line matching.

match() looks for the start of the line to match our regex, while search
just looks for the regex anywhere in the line.  I messed this up when
converting our greps in shell to python, which was part of breaking the
POWER_GOOD flake detection.  Most of our matches worked, but let's
consistently use this one so we don't mess this up in the future.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6529>