Revert "Add AES-256-CTR-HMAC-SHA512 Sframe cipher suites"

This reverts commit 0a4e15369bad2a99fdf784ab19f949b30346dfe9.

Reason for revert: conflicts with a change committed a bit earlier

Original change's description:
> Add AES-256-CTR-HMAC-SHA512 Sframe cipher suites
>
> Expose the three AES-256-CTR-HMAC-SHA512 cipher suites from
> draft-barnes-sframe-iana-256 (registry values 6, 7 and 8), already
> implemented by third_party/sframe, through SframeCipherSuite and map
> them in ToSframeCipherSuite. This brings the WebRTC enum in line with
> the eight suites listed in the WebRTC Encoded Transform
> SFrameCipherSuite IDL, which gained these suites in
> https://github.com/w3c/webrtc-encoded-transform/pull/303.
>
> Bug: webrtc:479862368
> Change-Id: Ie5f0bbcccfeee9ea7dd69b253c75c8c47082fbc7
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/507780
> Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
> Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
> Commit-Queue: Kacper Wasniowski <kwasniow@cisco.com>
> Cr-Commit-Position: refs/heads/main@{#48822}

Bug: webrtc:479862368
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: Ibac7b22070dff6034ce80a65ee2ff039814e6467
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/507940
Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#48823}