[🎨 Design] Blocked issues and epics icon/visualization should be consistent across Plan features

Summary

This is the UX design issue for &10623 (closed).

Proposal

The following changes are proposed for showing Blocked/Blocking relationships:

• Use the same relationship type icon for all work item types (today we use one specific for Issues)
  • Use entity-blocked icon for all Blocked instances
  • Use the new entity-blocking icon for all Blocking instances
• Show the relationship indicators in a common/shared location across views (currently the Blocked indicator is before Titles, whereas Blocking is along with other metadata)
• Include the count for both relationship types in all cases (we only show the count for Blocking today)
• Always include the popover with the icon/count indication (today we include a popover on Boards, but just a tooltip in other locations)
• Include both relationship indicators across the views consistently (some areas today we only show Blocked for example)