LMS Dashboard does not Remove Drop Badge from Students who Dropped and Re-added to the Course (Ongoing Write Up - Pending conclusion)

## Bug report form
### Steps to reproduce
1. Go to a course with an active student.
2. Access the LMS dashboard to see if the student's name is being recognized as part of the roster.
3. Unenroll the student from the course.
4. Wait for the next roster fetch of the LMS dashboard. (Student's name will now have a drop badge in the dashboard.)
5. Enroll the student back in the course.
6. Wait for the next roster fetch of the LMS dashboard.

### Expected behaviour
The roster fetch after the student has been added back to the course should reflect the correct status of the student. The student should no longer have a drop badge, indicating that he is now active in the course.

### Actual behaviour
Tell us what happens instead.
Student remains to have a drop badge after being added to the course and a new roster was fetched.

Additional documentation on what happens at each point of reproducing the issue: https://docs.google.com/document/d/18KfY8vc8rEEtFV6jqCjubpKjEc-jLM0b3vFjvx10Ke8/edit?tab=t.0