For H.265 when scalability mode is not configured for simulcast layers,
the default mode of L1T1 should be assumed instead of L1T3, as that is
the most commonly supported temporal scalability on all devices for
H.265.
Bug: chromium:41480904
Change-Id: Ia9bc91729eb393850dfe5e8fb04280b4f784560d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/369080
Commit-Queue: Jianlin Qiu <jianlin.qiu@intel.com>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43452}
d171832b6c