(CAT-2026) Update how `pdk test unit --list` detects an error #706

Job	Run time
spec (ruby 2.7) / spec	51s
spec (ruby 3.2) / spec	41s
acceptance (ruby 2.7 \| windows-2019) / acceptance	30m 38s
acceptance (ruby 3.2 \| ubuntu-latest) / acceptance	12m 7s
acceptance (ruby 2.7 \| ubuntu-latest) / acceptance	12m 37s
acceptance (ruby 3.2 \| windows-2019) / acceptance	7m 25s
	1h 4m 19s

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