Add Cut-off Date Configuration for Late Submissions in VPL Plugin

[pasupathi-raj]

We need an option in the Moodle VPL plugin to set a cut-off date for submissions.
Right now students can not submit after the due date, but we want a final cut-off date after which no submissions should be allowed.

What we need:

• Add a cut-off date setting in the VPL activity (similar to Moodle Assignment).

• After the cut-off date, students should not be able to submit or re-submit.

• Show a message like “Submissions are closed after the cut-off date.”