Update description for course content - view permission

Closes: DOC-1065

Test plan:
- In global navigation, open Permissions link
- Click Account Roles tab
- Click Course Content - view permission
- Expand What it Does heading in sidebar
- View New Gradebook addition

Change-Id: I54a74ff547767e791d8f5115a096bb5c546b7210
Reviewed-on: https://gerrit.instructure.com/197024
Tested-by: Jenkins
QA-Review: Erin Hallmark <erin@instructure.com>
Product-Review: Erin Hallmark <erin@instructure.com>
Reviewed-by: Steven Burnett <sburnett@instructure.com>

app/jsx/permissions/templates.js

@@ -1233,6 +1233,10 @@ const courseContentViewPermissions = generateActionTemplates(
     {
       title: I18n.t('Courses'),
       description: I18n.t('Allows user to view published and unpublished course content.')
+    },
+    {
+      title: I18n.t('New Gradebook'),
+      description: I18n.t('Allows user to view the New Gradebook.')
     }
   ],
   [