OPELMS assignment submission error descriptor

[tgoggans]

Using OPE LMS on laptop, when assignments are submitted to an assignment not configured to receive submissions an error is displayed stating Step 2 failed but does not provide additional info. It would be helpful to have an error referring to the assignment not currently configured to receive submissions. Additionally, an API modification to the OPE LMS to not display submission options when the current assignment is not configured to receive submissions would help point students away from attempting to submit in the wrong assignment.