Add "Finish Assessment" button for all assessments

[firasm]

TIL (thanks to Jessica Wong for asking and @nwalters512 for answering) that the "Finish Assessment" button only appears depending on your access rule settings:

My understanding is that that button only appears if real-time grading is disabled or if showClosedAssessment: false is set.

I think that "finish assessment" button should appear all the time rather than the standard workflow of this message:

When you are done, please logout and close your browser; there is no need to do anything else. If you have any saved answers when you leave, they will be automatically graded before your final score is computed.

---

I understand that the button doesn't actually "do" anything, but honestly, the satisfaction of clicking a button to end something is worth it compared to the anxiety of ending an exam by closing a browser window and walking away. I think for other cases, adding that button there will smooth out the workflow, we can even leave that text about saved answers there as-is.

Jessica Wong also said:

One of our first year programming classes (for non-majors) typically has a population that needs more reassurance over things like this. I think it would help them psychologically but I can always do the “say it 10 times in class and hope someone heard” thing :)

[jonatanschroeder]

I believe it's based on assessment type, not access rules.

[nwalters512]

While it's true that it's only ever shown for Exam-type assessments, it's not shown for all Exams. The actual conditions for when its shown is based on multiple factors, including access rules:

https://github.com/PrairieLearn/PrairieLearn/blob/88ee7bd271142a5a02c3cf12c39d1cf070651a52/apps/prairielearn/src/pages/studentAssessmentInstance/studentAssessmentInstance.ejs#L310-L347