Reorder Q050 before all other versions in server Alt-Svc
Reorder Q050 before all other versions in server Alt-Svc

In order for us to deploy h3-29 in Chrome without 0-RTT support, we'll want to have Chrome support both h3-29 and h3-Q050 and then have our servers prefer Q050 (Chrome follows the server's preference). This CL solves the server part of this.

All tests in this change are from cl/327732758.

Reorder QUIC alt-svc, protected by gfe2_reloadable_flag_quic_preferred_altsvc_version

PiperOrigin-RevId: 328245609
Change-Id: I7136fd131acd6a73ca7d2c26d3a1ed155adf076e

google/quiche,google/quiche,google/quiche,google/quiche