Added dynamic generation of exams as an option

src/utils/exams.be.ts

@@ -18,7 +18,7 @@ export const getExams = async (
   // added userId as due to assignments being set from the teacher to the student
   // we need to make sure we are serving exams not executed by the user and not
   // by the teacher that performed the request
-  userId: string
+  userId: string | undefined
 ): Promise<Exam[]> => {
   const moduleRef = collection(db, module);