No validation for the number of stars required for passing grade

[nicolopinci]

Describe the bug
It is possible to set any number of stars required for passing grade.

To Reproduce
Go in the grading tab for a CAPQUIZ topic and try to set the number of required stars to a value greater than 5.

Expected behavior
The number should be limited in the range 0 to 5.

[andstor]

I can confirm that it is indeed possible to set the Number of stars required for passing grade to a number higher than the number of stars defined within the activity.

A restriction should be added to limit the Number of stars required for passing grade to be lower than or equal to the number of stars defined in the activity.