Assessment: Show confirmation dialogue when accidentally leaving assessment page

[chrisknedl]

Is your feature request related to a problem?

When a tutor accidentally leaves the assessment without saving (be it through closing the tab or some shortcut), the entire grading progress is lost. This is very frustrating.

Describe the solution you'd like

Instead of just closing the tab/window, it would be nice to have a confirmation dialogue that asks the tutor if they really want to leave the page.

Describe alternatives you've considered

Auto-saving. However, sometimes tutors may write some feedbacks that they don't want to include in the report. Auto-saving takes away a degree of control here.

Additional context

No response