Hide archived projects only on workboards, not hovercards

Summary:
See PHI225. Previously, see D15335 / T10413. On workboards, we hide archived project tags since they aren't terribly useful in that context, at least most of the time. Originally, see T10349#159916 and D15297.

However, hovercards reuse this display logic, and it's inconsistent/confusing to hide them there, since the actual "Tags" elements on task pages show them. Narrow the scope of this rule.

Test Plan:

• Viewed a hovercard for a task with an archived project tagged, saw archived project.
• Viewed a workboard for the same task, saw only unarchived projects other than the current board tagged (this behavior is unchanged).

Reviewers: amckinley

Reviewed By: amckinley

Differential Revision: https://secure.phabricator.com/D18783