[3.13] gh-131339: test PyBytes_Size for a zero-size bytes object (GH-131340) (#131343)

gh-131339: test PyBytes_Size for a zero-size bytes object (GH-131340)
(cherry picked from commit 3ae67ba97e88d6f066a5b6f0c809f57fe4a1ecbe)

Co-authored-by: Nybblista <170842536+nybblista@users.noreply.github.com>