Resolve "Course codes for assignment filter are not correct"

What does this mr do?

Lab filter was not correct in shared labs because of the reason mentioned in issue #646 (closed), this fetches the appropriate information via id. Therefore there should be no mismatch.

Actions taken to fix bug

Get course code via ID.

Does this MR meet the acceptance criteria?

• I have added a changelog entry to reflect the significant changes I made and the bug I fixed.
• A test was created to test the bug.
• I have updated the documentation accordingly.
• I adhere to the style guide.

Closes #646 (closed)