Avoid losing Vector support

Vector is dropping the SkinTemplateToolboxEnd
hook (see I3c5d79f7742f0c1b5e471fd30146725c7dfc95f9)
To keep the link appearing in make use of the Sidebar hook.

Depends-On: Ie33f85a77299da8f3b98ab8b363761d1f8277708
Bug: T252917
Change-Id: I8c87a65ba73c5524785a44573bc11e361204bc7b