What problem are you trying to solve with Submitty

Currently, Cypress has no tests for a locked gradeable. The locked gradeable feature has been broken in the past, and a new course that is locked would make sure that this feature does not break in the first place

Describe the way you'd like to solve this problem

Make a new course that is locked by one of the open assignments, and click the button and make sure the popup says something similar to "you must finish x before doing this assignment"

Describe any potential alternatives you'd tried to solve the problem

Additional context

Related to #10791 and #10795