[HaTS] Do not show survey if UMA consent changed

We check user's UMA consent before start downloads, but didn't handle the case if user disable the UMA upload between the survey download starts and survey being shown.

Bug: 1355919
Change-Id: I01d191e9da93787da10be00fe99cf0b0cbdc4049
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3852427


Reviewed-by: Aishwarya Rajesh <aishwaryarj@google.com>
Reviewed-by: Theresa Sullivan <twellington@chromium.org>
Commit-Queue: Wenyu Fu <wenyufu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1041034}