Updated min bitrate for high-quality screenshare simulcast stream
Updated min bitrate for high-quality screenshare simulcast stream

The min bitrate is too low, and burstiness may cause overuse when first
enabling the stream, if the total available bitrate is low.

Bug: webrtc:9734
Change-Id: I399e0e809648f064feb87c73ece0c23a569b2750
Reviewed-on: https://webrtc-review.googlesource.com/99506
Reviewed-by: Ilya Nikolaevskiy <76788ac3efd229e9d156135d9ceb7fef65c45da4@webrtc.org>
Commit-Queue: Erik Språng <3ab8c90c99d6dd7822e0fad803ab0211dd287ae5@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#24678}
ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc