Add MPEG2 and MP4 Audio to types allowed in Captive Portal mode
<rdar://93934656>
<rdar://problem/94690689>
Pull request: https://github.com/WebKit/WebKit/pull/1404
Committed r295424 (251430@main): <https://commits.webkit.org/251430@main> Reviewed commits have been landed. Closing PR #1404 and removing active labels.