"Incomplete message" is showing up on revisit.

[fabiofilipegomes]

Subject of the issue/enhancement/features

The trickle extension shows the message "There is incomplete content above. You must complete this before you can proceed through the course." for screen readers on revisit.
The html properties are correctly updated when we complete the course (on_complete image attached - first image), but if we get back to the course after pressing the continue button or go home and then go to the completed course, the html properties are back to initial state (on_revisit image attached - second image).

Your environment

• version 7.0.0
• chrome, firefox, edge, opera, IOS Safari
• mobile & desktop

Steps to reproduce

1. Create a course with 1 mandatory component (can be a text question).
2. Create a component that will show up only when the mandatory component is completed (using Trickle extension settings).
3. Run the course using a screen reader (NVDA or JAWS).
4. First, try to advance without completing, the message "There is incomplete content above. You must complete this before you can proceed through the course." should appear (which is correct).
5. Complete the mandatory component.
6. The message disappears (correct until here) and the second component shows up.
7. Go home and then to the completed course again.
8. Try to advance until the end and you will see that the message "There is incomplete content above. You must complete this before you can proceed through the course." will appear for screen readers despite all the content is complete.

Expected behaviour

The message on step 8 above shouldn't appear.

Actual behaviour

The message on step 8 above is appearing for screen readers.

Screenshots (if you can)