Copying feedback session: mark session name as mandatory field when copying feedback session

[cedricongjh]

Description of feature/enhancement
When copying a feedback session, user is not notified why they are unable to copy the feedback session if the session name field is empty:

Let's append a * symbol after "Session Name", and display a red warning with an exclamation mark, stating "The field Session Name should not be empty," when the instructor clicks the field but leaves it empty, similar to #12617

[github-actions]

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