[SxS] Open link in split view via context menu

Right clicking a link should have an option to open that link in a new
split view with the active tab. If the active tab is already in a
split view, then the tab that isn't the source of the link should be
navigated to the link page.

Bug: 403351290
Change-Id: Icfda390b567d53dd52ca2d1731e070f164f2b7a5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6507814
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Teresa Mao <temao@chromium.org>
Commit-Queue: Steven Luong <stluong@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1457833}