Fix k5 detail view for multi role teachers

Teachers that are also students should not get the
K5 detail view.

fixes LS-2387
flag=none

Test plan:
- Have a user that is enrolled in a k5 subject course as
  both a student and a teacher
- View the subject course and click Manage Subject
- The course nav should be visible

Change-Id: I7b2c381a61418cd95c5f911c3ae9f151bb7b8a03
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/270149
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Product-Review: Nate Armstrong <narmstrong@instructure.com>
Reviewed-by: Robin Kuss <rkuss@instructure.com>
QA-Review: Robin Kuss <rkuss@instructure.com>

app/controllers/concerns/k5_mode.rb

@@ -30,7 +30,7 @@ module K5Mode
   # context is not a k5 course. Intended for use on pages that are not in a course context (like the courses index)
   def set_k5_mode(require_k5_theme: false)
     # Only students should see the details view
-    @k5_details_view = @context.try(:elementary_subject_course?) && @context.grants_right?(@current_user, :participate_as_student)
+    @k5_details_view = @context.try(:elementary_subject_course?) && !@context.grants_right?(@current_user, :read_as_admin)
     if @context.try(:elementary_subject_course?)
       @show_left_side = !@k5_details_view
     end

spec/controllers/concerns/k5_mode_spec.rb

@@ -67,7 +67,7 @@ describe K5Mode do
 
       context 'that is also a student' do
         before :each do
-          @course.enroll_user(@teacher, 'StudentEnrollment')
+          @course.enroll_user(@teacher, 'StudentEnrollment', enrollment_state: 'active')
         end
 
         it_behaves_like ':show_left_side'