Bug fixes for progress tracking

[mbarton]

Follow up to #1058

• Show progress sticky
• The question total is only the visible questions
• Don't show generated parent questions (eg 3.5) as incomplete
• Don't show "No" as incomplete
• Don't crash if no submission exists

[mbarton]

Seen on STAGING, LIVE (merged by @mbarton 28 minutes and 42 seconds ago) Please check your changes!