Allow adding legacy issues as child of Epic Work Item via Hierarchy Widget
Summary
With #434169 (closed), users are now able to associate Epic Work Item as parent of a legacy issue using Epics dropdown in the Issue right sidebar (after enabling display_work_item_epic_issue_sidebar
for a given project).
As a continuation of this feature, we should allow pasting legacy issue URL within Hierarchy widget of Epic Work Item to add it as a child, which isn't happening currently as backend is unable to parse the Issue URL on hierarchy widget to tokenize it;
Edited by Kushal Pandya