Reland "SCReAM: Scale backoff by feedback interval and reset ref window on congestion"

This is a reland of commit 6214048b9dccb3abf7e1ab858396c4cfb0849703
Internal tests are fixed.

Original change's description:
> SCReAM: Scale backoff by feedback interval and reset ref window on congestion
>
> This CL:
> 1. Tracks feedback interval in ScreamV2 and scales backoff relative
>    to effective virtual RTT (max of virtual RTT and feedback interval)
>    to account for how often feedback actually arrives. This avoids
>    stalled backoff during low bitrate audio with large feedback intervals.
> 2. Clamps the reference window to data in flight on first congestion
>    in delay-based congestion control to eliminate initial rampup overshoot.
> 3. Adds 'FeedbackIntervalAvgG' and 'UseFeedbackIntervalForVirtualRtt'
>    parameters to ScreamV2Parameters.
> 4. Tightens expectations in AudioOnlyBothDirectionsLinkCapacity40To90KbpsRtt200ms
>    to reflect lower RTT and tighter BWE.
>
> Bug: webrtc:447037083
> Change-Id: I79d8cfff9e4ac034d8192a3668ea3342812ce141
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/506900
> Commit-Queue: Per Kjellander <perkj@webrtc.org>
> Reviewed-by: Björn Terelius <terelius@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#48777}

Bug: webrtc:447037083
Change-Id: I2c09879692744a39720a52b5916757a4797e1f05
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/507460
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#48788}