(CAT-2026) Update how `pdk test unit --list` detects an error #701

Job	Run time
spec (ruby 2.7) / spec	49s
spec (ruby 3.2) / spec	40s
acceptance (ruby 2.7 \| windows-2019) / acceptance	32m 21s
acceptance (ruby 2.7 \| ubuntu-latest) / acceptance	12m 11s
acceptance (ruby 3.2 \| ubuntu-latest) / acceptance	12m 27s
acceptance (ruby 3.2 \| windows-2019) / acceptance	7m 41s
	1h 6m 9s

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