Expose `SinkTypeIR::Partitioned` in the Python node visitor

This struct contains the information we need in the logical plan to implement partitioned sinks. Specifically in /home/coder/polars/crates/polars-plan/src/dsl/options/sink.rs

```rust
pub struct PartitionedSinkOptionsIR {
pub base_path: PlRefPath,
pub file_path_provider: FileProviderType,
pub partition_strategy: PartitionStrategyIR,
pub file_format: FileWriteFormat,
pub unified_sink_args: UnifiedSinkArgs,
pub max_rows_per_file: IdxSize,
pub approximate_bytes_per_file: u64,
}
```