Resolve "[Queue-2.0] Slotted lab not loading for Student"

What does this mr do?

Make sure that thymeleaf has access to the data object from the SlottedLabViewDTO.

Actions taken to fix bug

Add method getData to SlottedLabViewDTO to make sure this object is available to thymleaf and add test to make sure this erroring thymeleaf page is being displayed correctly.

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 #386 (closed)