disable scroll for emails in course

- looks ugly with them on windows and linux
- can easily get the email via student toggle

Author: williamstein

src/packages/frontend/course/students/students-panel-student.tsx

@@ -576,7 +576,7 @@ export function Student({
           </h6>
         </Col>
         <Col md={4}>
-          <h6 style={{ color: "#666", overflow: "auto" }}>
+          <h6 style={{ color: "#666", overflow: "hidden" }}>
             {render_student_email()}
           </h6>
         </Col>