[BUG] When Grading multiple assignments, if one is unable to be found, no assignments will be graded

[gregbell26]

Description

Issue

When selecting multiple assignments to grade, after all common names have been mapped to assignments, if the path to Gradescope grades is not found, no further grades are able to be entered.

Solution

If unable to find a grade sheet, then inform the user that the assignment will be skipped in grading and will update the list of assignments to grade by removing the assignment. Then continue to grade the remaining assignments.

Acceptance Criteria

• Uses Canvas API to remove the assignment from the list of assignments to grade.
• Displays message to the user stating that assignment will be skipped.
• Correctly displays a number of assignments to grade later in the program.
• Allows users to continue grading while skipping assignments with a missing grade book.