fix(ui): honor new-tab preference on entry titles
When "Read articles by opening external links" is enabled, the entry
title routes to an internal handler that HTTP-redirects to the external
URL. The title link had no target="_blank", so the redirect was followed
in the current tab, ignoring "Open external links in a new tab".
Add target="_blank" to the title link in every entry list template when
both preferences are enabled.
Refs: #4241