Fixing non-second timedelta64 bug #396

Job	Run time
mypy	4m 2s
py3.13 \| macos \| integration tests	13m 1s
py3.13 \| macos \| unit tests	8m 5s
py3.13 \| ubuntu \| integration tests	17m 2s
py3.13 \| ubuntu \| unit tests	13m 7s
py3.13 \| windows \| integration tests	30m 36s
py3.13 \| windows \| unit tests	18m 29s
py3.10 \| ubuntu \| integration tests	17m 24s
py3.10 \| ubuntu \| unit tests	12m 44s
py3.11 \| ubuntu \| unit tests	12m 46s
py3.12 \| ubuntu \| unit tests	13m 40s
merge-test-artifacts	6s
	2h 41m 2s

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