Remove deprecated Parquet metadata / statistics APIs that are past the API health policy

### Is your feature request related to a problem or challenge?

The [API health policy deprecation guidelines] say deprecated APIs remain for

> 6 major versions or 6 months, whichever is longer

`main` is at `55.0.0`, so the next release is `56.0.0` and anything deprecated in `50.0.0` or earlier can now be removed.

Four such items remain in the `datafusion-datasource-parquet` crate:

| Item | Deprecated in | Replacement |
| --- | --- | --- |
| [`fetch_parquet_metadata`](https://github.com/apache/datafusion/blob/main/datafusion/datasource-parquet/src/file_format.rs#L654) | 50.0.0 | `DFParquetMetadata::fetch_metadata` |
| [`fetch_statistics`](https://github.com/apache/datafusion/blob/main/datafusion/datasource-parquet/src/file_format.rs#L677) | 50.0.0 | `DFParquetMetadata::fetch_statistics` |
| [`statistics_from_parquet_meta_calc`](https://github.com/apache/datafusion/blob/main/datafusion/datasource-parquet/src/file_format.rs#L699) | 50.0.0 | `DFParquetMetadata::statistics_from_parquet_metadata` |
| [`ParquetSource::predicate`](https://github.com/apache/datafusion/blob/main/datafusion/datasource-parquet/src/source.rs#L395) | 50.2.0 | `ParquetSource::filter` |

[API health policy deprecation guidelines]: https://datafusion.apache.org/contributor-guide/api-health.html#deprecation-guidelines
[upgrade guide]: https://github.com/apache/datafusion/tree/main/docs/source/library-user-guide/upgrading

### Describe the solution you'd like

Remove all four items and supporting code

* While this is a breaking Rust API change, the PR should carry the `api change` label
* DO NOT add a note to the `56.0.0` [upgrade guide], as removing deprecated APIs is clear and the compiler has guided people off them in the past

### Describe alternatives you've considered

N/A

### Additional context

Follow on to #23080, which did the same sweep at the `49.0.0` cutoff, and #24535.