[bookmarks] Enable butter by default

Bug: None
Change-Id: I57a6a99528785171f50c1e21106eef92f7afe1cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5577278


Commit-Queue: Brandon Wylie <wylieb@google.com>
Reviewed-by: Victor Vianna <victorvianna@google.com>
Cr-Commit-Position: refs/heads/main@{#1312124}