Change Epic work item path from /work_items/ to /epics/

Overview

In &13514 (comment 1881415231), we discussed how URLs are currently changing for Epic work items, and the need for redirects for the near term. Additionally, we discussed the option of reverting back to using /epics/ as the path for Epics in the near term, as that aligns better with the current state (Epics living separately in product). It was also discovered in #463156 (comment 1920045878) that the IID will continue to remain the same for Epics post-migration, which means the only thing changing in the URL for detail pages is /epics/ to /work_items/.

Proposal

Change the Epic work item detail page to use /epics/ instead of /work_items/ in the URL path.

Question: If we can achieve this (and the effort is fairly low), does this mean we would no longer need to account for URL redirects (and issues like #463155 (closed))?