Reland "[Bookmarks] Show a promo when the bookmark bar is auto-hidden."

This is a reland of commit d3caa3bce2fffbfc6eb46b5ac7315b57abc27f30
The original CL was reverted because it was suspected to be the culprit CL for these two interactive ui tests:
HelpBubbleHandlerInteractiveUiTest.ElementBecomesHiddenOnSecondaryUISwap and WallpaperSearchOptimizationGuideInteractiveTest.CustomizeButtonsWorkTogether failures.

But after the CL was reverted, at commit position #1646144, these two cases were still failing at #1646147. https://ci.chromium.org/ui/p/chromium/builders/ci/win11-arm64-rel-tests/7376/blamelist

Therefore, the original CL was not the culprit for the test failure.

Original change's description:
> [Bookmarks] Show a promo when the bookmark bar is auto-hidden.
>
> When the bookmark bar is automatically hidden due to inactivity, trigger
> the `kIPHBookmarkBarSimplifiedFeature` promo. Updates a unit test to
> verify this behavior.
>
> Make sure the promo shows and only once, and clicking the undo button
> restores the bookmark bar on NTP:
> https://screencast.googleplex.com/cast/NjY3NzQxNTcxMDQyNTA4OHw5MTg1MGZiZC0yOA
>
> If the toast is dismissed, the bookmark bar visibility state stays
> "Always Hide":
> https://screencast.googleplex.com/cast/NDU0OTcxOTI0NTE5MzIxNnwyNmE4ODYzMi1kOA
>
> Fixed: b:520023694
> Change-Id: If8312ec376f458e1584ba2d6071ae866699e8d78
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7922377
> Commit-Queue: Bofeng Chen <bofengchen@google.com>
> Auto-Submit: Bofeng Chen <bofengchen@google.com>
> Reviewed-by: Riley Tatum <rtatum@google.com>
> Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1645751}

Change-Id: Ibdb130071afe441862a15f3a18e38418d58d3dd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7934748
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Commit-Queue: Bofeng Chen <bofengchen@google.com>
Reviewed-by: Riley Tatum <rtatum@google.com>
Cr-Commit-Position: refs/heads/main@{#1646515}