feat: notify the user if a sequence is hidden because of due date (#636)

Normally, these sequences are skipped. But if the user manually
goes to the section, they should be notified why they can't access
it. That can easily happen if they bookmarked the page or something.

AA-1000

src/courseware/data/pact-tests/lmsPact.test.jsx

@@ -331,6 +331,7 @@ describe('Courseware Service', () => {
             item_id: string('block-v1:edX+DemoX+Demo_Course+type@sequential+block@basic_questions'),
             is_time_limited: boolean(false),
             is_proctored: boolean(false),
+            is_hidden_after_due: boolean(false),
             position: null,
             tag: boolean('sequential'),
             banner_text: null,
@@ -367,6 +368,7 @@ describe('Courseware Service', () => {
           },
           isTimeLimited: false,
           isProctored: false,
+          isHiddenAfterDue: false,
           activeUnitIndex: 0,
           saveUnitPosition: false,
           showCompletion: false,