Use PG int type to represent DuckDB tinyint type

[JelteF]

Description

We're currently representing tinyint as bpchar. While that saves on the, it means it is not displayed as a number but as a hex character by postgres clients. Lets instead convert it to a Postgres integer, because that UX problem is probably not worth the space savings to anyone.

Once we do this we can also un-exclude it from this test:

pg_duckdb/test/regression/expected/test_all_types.out

Line 6 in 02ebeae

tinyint, -- PG14 outputs this differently currently