Add coursewide percentage correct to the Problem Attempts and Results table on the At-Risk Learner Dashboard

[crathbun428]

User Story
As a course delivery team member, I want to see a new Course-wide % correct column in the Problem Attempts and Results table on the At-Risk Learners Dashboard, so that I can easily compare how every learner in the course who answered a given problem performed versus the selected learner(s).

Acceptance Criteria
Given I have access to the At-Risk Learners Dashboard
When I view the Problem Attempts and Results table
Then I see a new Course-wide % Correct column to the left of the % Correct column
And the % Correct column is renamed to Selected Learner(s) % Correct
And (if possible) Visually indicate when Selected Learner(s) % Correct is lower, equal to, or higher than Course-wide % Correct