Revert "Per default enable RobustThroughputEstimator"

This reverts commit d017b1e306186252ed52ab84459d05efc4eb9fd4.

Reason for revert: Breaks downstream test.

Original change's description:
> Per default enable RobustThroughputEstimator
>
> Experiments has not showed significant metric changes. However, simulations has showed that RobustThroughputEstimator better follow the actually receive rate better. Especially during bursts of sent packets. Code is also simpler.
>
>
> Bug: webrtc:13402 chromium:1411666
> Change-Id: I38c309f74e8e1322602196354545b3a465866263
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/318040
> Reviewed-by: Björn Terelius <terelius@webrtc.org>
> Commit-Queue: Per Kjellander <perkj@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#40653}

Bug: webrtc:13402 chromium:1411666 b/298001595
Change-Id: Ic68ef954f462021e991f3183b94d85eb6a44fac0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/318141
Owners-Override: Mirko Bonadei <mbonadei@webrtc.org>
Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#40658}