The `parse_header_parameters` function historically used Python's `cgi`
module (now deprecated). In 34e2148fc725e7200050f74130d7523e3cd8507a,
the logic was inlined to work around this deprecation ( #33173). Later,
in d4d5427571b4bf3a21c902276c2a00215c2a37cc, the header parsing logic
was further cleaned up to align with `multipartparser.py` (#33697).
This change takes it a step further by replacing the copied `cgi` logic with
Python's `email.message.Message` API for a more robust and maintainable header
parsing implementation.
Thanks to Raphael Gaschignard for testing, and to Adam Johnson and Shai
Berger for reviews.
Co-authored-by: Ben Cail <bcail@crossway.org>
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>