Add user status evaluator_role_requested to admin action required

[emmabjj]

Description

Add new valid user status evaluator_role_requested to show up in admin action required and give it a yellow status color.

Given an existing user with status evaluator_role_requested, when assigned to a challenge phase in the Rails app,
then that user shows up in the Phoenix app as admin action required and the admin can activate that user.

Related Issues

#287

Changes Made

• Include evaluator_role_requested user status to statuses of users_requiring_action
• Add yellow status to 'Evaluator Role Requested'

Screenshots (if applicable)

Checklist

• PR is assigned to a project: Challenge_gov Board
• PR is assigned to a milestone: current sprint
• GH issues are assigned to the PR (under Development section on the right hand side)
• PR is assigned a reviewer, and requires code review and approval by a teammate
• New functionality is tested and all tests are green
• I have added unit tests for new functionality or updated existing tests for changes.
• I have updated the documentation/README accordingly, if necessary.
• If you have DB migration, it is a "safe" migration and you've confirmed it can be rolled back.
• If applicable, Controllers modified contain appropriate authorization plugs
• This PR has been reviewed by at least one other team member.
• Build has been approved for deployment in CircleCI.