feat: Allow datafusion-ffi to opt out of proto parquet

[Xuanwo]

Which issue does this PR close?

N/A

Rationale for this change

datafusion-ffi inherits datafusion-proto from the workspace. Because datafusion-proto enables its parquet feature by default, downstream crates that depend on datafusion-ffi also pull in datafusion-datasource-parquet, parquet, and parquet compression dependencies even when they do not need parquet-aware proto support.

Cargo features are additive, so downstream users cannot opt out by disabling default features on their own direct datafusion-proto dependency if the datafusion-ffi -> datafusion-proto edge has already enabled defaults.

What changes are included in this PR?

This PR makes the workspace datafusion-proto dependency default to default-features = false, then lets crates opt into the previous behavior explicitly.

For datafusion-ffi, the previous default behavior is preserved with a new default parquet feature. Downstream users that want to avoid parquet dependencies can now use datafusion-ffi with default-features = false.

The FFI session table option bridge now gates ConfigFileType::PARQUET usage behind the datafusion-ffi/parquet feature, while still preserving parquet table option values in no-default builds.

Are these changes tested?

Yes. Existing datafusion-ffi tests pass with default features and with --no-default-features. The feature graph was also checked to confirm that default datafusion-ffi still enables parquet, while datafusion-ffi --no-default-features does not include datafusion-datasource-parquet.

Are there any user-facing changes?

Default behavior is unchanged. Users can now opt out of parquet-aware proto support from datafusion-ffi by disabling datafusion-ffi default features.

[waynexia]

Looking good