Attendance: Student view of comment window - change "Cancel" to "Close"

[mpellicer]

Original issue reported here:

https://jira.sakaiproject.org/browse/SAK-41577

Test plan:

In the Attendance tool, in a site with at least one student, create an attendance event.
Click in to the attendance event and mark the student as "Absent."
Click on the empty comment bubble and enter a comment. Save.

Log in as the student.
Navigate to the Attendance tool.
Click on the comment bubble for the attendance item. Read the comment.

What happens: To close the comment window, student clicks "Cancel."

What I suggest: Would probably make more sense for student to click "X" or "Close" when completing a passive action.