Add number of learners passed to Pathway dashboard

User Story

As a course team member, I want to see the number of learners that have passed the currently filtered pathways, so that I can quickly access this number for monitoring and reporting purposes.

Acceptance Criteria

Description: An N Passed big number has been added to the Enrollment and Completion section of the Pathway Dashboard
Given I am a user with access to the Pathway Dashboard
When I view the Enrollment and Completion section under the Pathway Overview/Summary section toward the top of the dashboard
Then I see an N Passed big number showing the number of learners who have passed all courses within the currently filtered Pathway(s) (Note: I want this number to be unduplicated, so if the same learner has passed 2 different currently-filtered pathways, they only show up in the count once).
And I see that there is helper text on hover via a tooltip that indicates that: This number is an unduplicated number of learners who have passed currently-filtered pathway(s).

Start at the Pathway Dashboard's Enrollment and Completion section under Pathway Overview/Summary. Trace how the currently filtered pathways and existing big numbers are assembled, then verify that the new N Passed value counts each learner once and that its tooltip explains the unduplicated count.