net/mediastreamer: Update to 5.1.55

Add QTGL option and enable it by default, this is needed by net/linphone
for working video calls.

Changelog: https://gitlab.linphone.org/BC/public/mediastreamer2/-/tags

PR: 266006, 266017
Approved by: bofh (maintainer, via IRC), tcberner (mentor)
Suggested by: Ruslan Zalata <rz@fabmicro.ru>
Differential Revision: https://reviews.freebsd.org/D36458