Rebuild gradeable stuck on in rebuild queue

[poorna2152]

Describe the bug
When Rebuild Gradeable button of a Gradeable is clicked build status is stuck on is in the rebuild queue.

Expected behavior
Build status should go into Gradeable build complete after some time.

To Reproduce
Steps to reproduce the behavior:

1. Log in as an instructor
2. Go to a edit gradeable page for any gradeable
3. Click the Submissions\Autograding tab
4. Click the Rebuild Gradeable button

Additional context
Managed to solve this using command apt-get install libgl1 as suggested by @Viyerelu23333

[Viyerelu23333]

Just had a look into this issue...

It is introduced by dependabot in ba8145e. There is also a related issue at opencv/opencv-python#370.

[MasterOdin]

Looks like the potential fixes are:

• Install libgl1-mesa-glx (while installing just libgl1 fixes the immediate problem, no telling what other X11 things might be required in the future)
• Replace opencv-python with opencv-python-headless in our pip install, which does not include the X11 stuff

@shailpatels Not sure your thoughts on difficulty of switching over to headless? Probably just have a migration that does pip list to check if opencv-python is installed, and then replaces that with opencv-python-headless if we want to be extra safe?

[shailpatels]

@MasterOdin Yeah switching to opencv-headless I think is the better option since the X11 stuff is never actually used anywhere
made #8156 to fix this issue with the migration

So far didn't see any issues testing the bulk upload functions since it only uses the core opencv modules