`style` not included in `utils.get_field_kwargs()`; not aligned to DRF core arguments

[regoawt]

Currently, if style is defined as a kwarg on a mongoengine field, utils.get_field_kwargs() method does not build the DRF serializer field with it. To achieve this one has to wrap serializers.build_field() and update the field_kwargs dictionary, which seems unnecessary?

Is this intended behaviour?

The style argument is listed as a DRF 'core argument' on the base serializer field:
https://www.django-rest-framework.org/api-guide/fields/#core-arguments

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[BurkovBA]

@regoawt Hello.

I might be wrong, but I feel like style is a relatively new field in DRF.

Thank you for your PR .Please, add unit-tests to your changes, so that we could ensure their correctness.