[3.13] gh-131020: py.exe launcher does not correctly detect a BOM when searching for the shebang (GH-131021) (#131047)

gh-131020: py.exe launcher does not correctly detect a BOM when searching for the shebang (GH-131021)
(cherry picked from commit 36ef3bfe39d767e283b55fe86f34e7671b7f5d1c)

Co-authored-by: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>