Fixing non-second timedelta64 bug #391

Job	Run time
mypy	3m 43s
py3.13 \| macos \| unit tests	8m 38s
py3.13 \| macos \| integration tests	13m 45s
py3.13 \| ubuntu \| unit tests	12m 53s
py3.13 \| ubuntu \| integration tests	17m 45s
py3.13 \| windows \| unit tests	20m 16s
py3.13 \| windows \| integration tests	28m 6s
py3.10 \| ubuntu \| unit tests	12m 49s
py3.10 \| ubuntu \| integration tests	18m 29s
py3.11 \| ubuntu \| unit tests	12m 50s
py3.12 \| ubuntu \| unit tests	13m 4s
merge-test-artifacts	4s
	2h 42m 22s

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