graphics/mesa: Update to 24.0.6

Release notes: https://lists.freedesktop.org/archives/mesa-dev/2024-April/226190.html
Release notes: https://lists.freedesktop.org/archives/mesa-dev/2024-April/226200.html

Differential Revision: https://reviews.freebsd.org/D44941
Sponsored by: Beckhoff Automation GmbH & Co. KG