Remove unused include in //chrome's safe_browsing_service.cc

I'm analyzing this file for potential componentization, and removing
unused //chrome includes helps to clarify the task (besides being good
hygiene in any case).

Bug: 1226567
Change-Id: Id527738851d8fbaed4438451a44297b2b0c8b067
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3140380


Commit-Queue: Colin Blundell <blundell@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Auto-Submit: Colin Blundell <blundell@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/main@{#918544}