Revert "[skyvault] Invoke drive upload cancel"

This reverts commit 2fa171d2d105993f71dae3d69161c100ade1e931.

Reason for revert: CancelUpload test is failing. See http://b/374810450 for details.

Original change's description:
> [skyvault] Invoke drive upload cancel
>
> Invokes the DriveSkyvaultUploader::Cancel() method, when the entire
> migration process is cancelled.
>
> R=poromov@chromium.org
>
> Fixed: 349097807
> Change-Id: I7909cac2a629b9fe7252e9897d0acd233ffea547
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5939175
> Reviewed-by: Sergey Poromov <poromov@chromium.org>
> Commit-Queue: Aida Zolic <aidazolic@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1371452}

Change-Id: I8806da6a51024f1a3d8b80818e96ca6916097365
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5950244
Auto-Submit: Darwin Yang <darwinyang@chromium.org>
Reviewed-by: Orin Jaworski <orinj@chromium.org>
Owners-Override: Darwin Yang <darwinyang@chromium.org>
Commit-Queue: Orin Jaworski <orinj@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1371646}