max() drops field metadata / extension type from its result (first_value keeps it) #26916

Describe the bug

max() (and likely min()) drops field metadata, including Arrow extension types, from its result. first_value() keeps it, so aggregates are inconsistent.

Found while reviewing #21714. Reproduces on main with any metadata-carrying column (e.g. table_with_metadata in metadata.slt), so it predates that PR.

To Reproduce

On #21714:

CREATE TABLE u (id UUID);
INSERT INTO u VALUES (X'00010203040506070809000102030506');

SELECT arrow_metadata(max(id), 'ARROW:extension:name') FROM u;          -- NULL
SELECT arrow_metadata(first_value(id), 'ARROW:extension:name') FROM u;  -- arrow.uuid

On main, in metadata.slt:

SELECT arrow_metadata(max(id), 'metadata_key') FROM table_with_metadata;          -- NULL
SELECT arrow_metadata(first_value(id), 'metadata_key') FROM table_with_metadata;  -- the id field

Expected behavior

max / min return a value of the same type as their input, so the result field should keep the input's metadata (as first_value does).

For comparison, DuckDB: typeof(max(uuid_col)) is UUID and typeof(max(json_col)) is JSON.

Additional context

Related: #21981 (MinAccumulator dropping inner-field metadata for lists).