CodeHealth: Convert HostContentSettingsMap::GetWebsiteSetting

Remove deprecated usage and replace with new base::Value API.

Bug: 1281896
Change-Id: Icb613e800f54ba4c908889ad3e558e8bb1ef0217
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3365266


Reviewed-by: Balazs Engedy <engedy@chromium.org>
Reviewed-by: danakj chromium <danakj@chromium.org>
Owners-Override: danakj chromium <danakj@chromium.org>
Commit-Queue: Christian Dullweber <dullweber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#958038}