[Variant] Unify the CastOptions usage in parquet-variant-compute

[klion26]

Which issue does this PR close?

• Closes [Variant] Unify the cast option usage in ParquentVariant #8873 .

What changes are included in this PR?

Unify the CastOptions usage in parquet-variant-compute

Currently, there is only arrow::compute::CastOptions in parquet-variant-compute now, the existing parquet-variant-compute/CastOptions has replaced by the arrow::compute::CastOptions with the equal behavior

Are these changes tested?

The existing tests covered the logic

Are there any user-facing changes?

This will break some public API in parquet-variant-compute, but this crate is experiment now, so maybe we don't need to wait for a major release.

[klion26]

@alamb this pr unified the usage of CastOptions for paruqet-variant-compute(will use arrow-cast/CastOptions), but it would break some public api in parquet-variant-compute, as parquet-variant-compute is experiment now, not sure if we need to wait for the next major version. If we need to wait for the next major version, I'll attach the api-change tag here.

[alamb]

Thanks @klion26 -- this looks good to me

I agree it is an API change but since we have marked Variant as experimental we can still change it in a non-major release