Revert "[bookmarks] Only remove specific index when a deletion occurs"

This reverts commit 33497a99ba093b3b3098c1b49651792716096ec5.

Reason for revert: Causing tree closure

Original change's description:
> [bookmarks] Only remove specific index when a deletion occurs
>
> Prevents a large refresh event which potentially could cause an ANR.
> When testing locally with ~3000 bookmarks, this operation still drags
> potentially because the underlying modellist is shifting elements.
> Still requires some work, but this should improve the performance
> overall.
>
> Bug: 1458276
> Change-Id: Iaaa9cfc504a77fc4c87a970f0e09ab15c592fa66
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4728308
> Commit-Queue: Brandon Wylie <wylieb@chromium.org>
> Reviewed-by: Sky Malice <skym@chromium.org>
> Code-Coverage: Findit <findit-for-me@appspot.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/main@{#1179174}

Bug: 1458276
Change-Id: Ib1ef7930438a9127dda19b3eb81c1731c7b767ae
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4749404
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Steven Luong <stluong@chromium.org>
Owners-Override: Steven Luong <stluong@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1179191}