Update default value of particlefile chunks to length of pset #369

Job	Run time
py3.13 \| macos \| unit tests	8m 19s
py3.13 \| macos \| integration tests	18m 38s
py3.13 \| ubuntu \| unit tests	13m 1s
py3.13 \| windows \| unit tests	22m 11s
py3.10 \| ubuntu \| unit tests	12m 59s
py3.11 \| ubuntu \| unit tests	12m 57s
mypy	3m 57s
py3.12 \| ubuntu \| unit tests	14m 21s
py3.13 \| ubuntu \| integration tests	17m 26s
py3.13 \| windows \| integration tests	31m 34s
py3.10 \| ubuntu \| integration tests	17m 39s
merge-test-artifacts	8s
	2h 53m 10s

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