Remove old deprecated code

Follow on to working on #23029

The API health policy deprecation guidelines say deprecated methods remain for

6 major versions or 6 months, whichever is longer

Thus, as of now when we are working on 55.0.0. anything deprecated in 49.0.0 or earlier clears the six-major-version side of the policy

Here is a list of possible candidate code we can remove. I suggest creating individual PRs for each item (or similar ones) to speed up review and merge

Deprecated API Removal Candidates

Obvious Candidates

UnionExec::new, deprecated in 44.0.0. Replacement: UnionExec::try_new.
DFParser::new and DFParser::new_with_dialect, deprecated in 46.0.0. Replacement: DFParserBuilder.
datafusion_sql::{ResolvedTableReference, TableReference} re-exports, deprecated in 46.0.0. Replacement: import from datafusion_common.
ScalarValue::raw_data, deprecated in 46.0.0. Replacement: to_array.
Signature::get_possible_types, deprecated in 46.0.0. Replacement: get_example_types.
RowIndex, deprecated in 46.0.0 and appears unused outside its definition.
ViewTable::try_new, deprecated in 47.0.0. Replacement: ViewTable::new.
DFSchema::check_arrow_schema_type_compatible, deprecated in 47.0.0 and appears definition-only.
coerce_file_schema_to_view_type and coerce_file_schema_to_string_type, deprecated in 47.0.0. Replacement: apply_file_schema_type_coercions.
create_writer, deprecated in 48.0.0 and appears definition-only. Replacement: ObjectWriterBuilder::new(...).
Filter::try_new_with_having, deprecated in 48.0.0 and appears definition-only. Replacement: try_new.

More Invasive Candidates

DiskManagerConfig, DiskManager::try_new, and RuntimeEnvBuilder::with_disk_manager, deprecated in 48.0.0. Eligible, but removal touches runtime configuration plumbing.
Expr::Wildcard, deprecated in 46.0.0. Eligible, but higher risk because it is an enum variant and may affect downstream pattern matches.
Old Substrait variation constants in variation_const.rs, deprecated in 41.0.0 to 43.0.0. Eligible, but currently used internally to consume older Substrait encodings, so removal may be a compatibility decision rather than mechanical cleanup.