Revert "[waffle] Fix SearchEngineChoiceJsBrowserTest being flaky"

This reverts commit af7a90b56e8a533d2e983bf1e83391b33e94639c.

Reason for revert: More test failure observed.

Original change's description:
> [waffle] Fix SearchEngineChoiceJsBrowserTest being flaky
>
> The flake was cause by the scrolling animation. We disable it
> to make the test more stable.
>
> Bug: b:309575766
> Fixed: 1509119
> Change-Id: Icc68a841f66955728653abfc2224e076b8a98414
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5119726
> Reviewed-by: Nicolas Dossou-Gbété <dgn@chromium.org>
> Commit-Queue: Jack Yammine <jyammine@google.com>
> Cr-Commit-Position: refs/heads/main@{#1238042}

Bug: b:309575766, 1512184
Change-Id: I20ef447a747117dcf11df3eaaee90fe2069cf9f3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5125846
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1238261}