Remove `netcdf_engine` from Field and FieldSet #689

Job	Run time
mypy	1m 16s
py3.13 \| macos \| unit tests	1m 15s
py3.13 \| macos \| integration tests	1m 16s
py3.13 \| ubuntu \| unit tests	1m 15s
py3.13 \| ubuntu \| integration tests	1m 15s
py3.13 \| windows \| unit tests	1m 6s
py3.13 \| windows \| integration tests	1m 10s
py3.10 \| ubuntu \| unit tests	1m 12s
py3.10 \| ubuntu \| integration tests	1m 15s
py3.11 \| ubuntu \| unit tests	1m 13s
py3.12 \| ubuntu \| unit tests	1m 14s
merge-test-artifacts	1s
	13m 28s

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