feat: restrict admin actions based on the settings configuration.

[andrey-canon]

Description

This removes the old pearson vue admin implementation in favor of the pearson engine feature, this also allow to control the action visibility based on the USE_PEARSON_ENGINE_SERVICE value

Testing instructions

1. Set the setting USE_PEARSON_ENGINE_SERVICE to false
2. Go to /admin/student/courseenrollment/
3. Check that there are no actions
4. Set the setting USE_PEARSON_ENGINE_SERVICE to true
5. Go to /admin/student/courseenrollment/
6. Check that the Pearson actions appear

[johanseto]

Working in my local env.