Removing Field.to_write and FieldSet.to_write methods #753

Job	Run time
mypy	3m 39s
py3.13 \| macos \| integration tests	21m 19s
py3.13 \| macos \| unit tests	7m 37s
py3.13 \| ubuntu \| integration tests	13m 52s
py3.13 \| ubuntu \| unit tests	9m 9s
py3.13 \| windows \| integration tests	25m 42s
py3.13 \| windows \| unit tests	13m 32s
py3.10 \| ubuntu \| integration tests	25m 0s
py3.10 \| ubuntu \| unit tests	10m 30s
py3.11 \| ubuntu \| unit tests	10m 20s
py3.12 \| ubuntu \| unit tests	9m 59s
merge-test-artifacts	3s
	2h 30m 42s

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