This switches the order of what renderer mode is tried first, so that
the gbm renderer mode is preferred on an NVIDIA driver where it is
supported.
We fall back to still try the EGLDevice renderer mode if the created gbm
renderer is not hardware accelerated.
The last fallback is still to use the gbm renderer, even if it is not
hardware accelerated, as this is needed when hardware acceleration isn't
available at all. The original reason for the old order was due to the
fact that a gbm renderer without hardware acceleration would succeed
even on NVIDIA driver that didn't support gbm.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2051>
8fc1325e8e