[3.12] gh-113659: Skip hidden .pth files (GH-113660) (GH-114143)

Skip .pth files with names starting with a dot or hidden file attribute.
(cherry picked from commit 74208ed0c440244fb809d8acc97cb9ef51e888e3)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>