Replace parse_header (removed in Django 4.2) with parse_header_parameters

[Scotchester]

Discussed in #8539

^{Originally posted by Scotchester June 29, 2022}
Hi folks,

The Wagtail project has a check against Django's main branch in our CI, and it started failing a day or two ago due to the removal of django.http.multipartparser.parse_header(), which DRF uses in three places. This change will be released in Django 4.2.

The recommended solution is to switch to django.utils.http.parse_header_parameters().