[#12679] & [#12653] Copying feedback session: Name for copied session should not be whitespace & Copy course modal: Mandatory fields not highlighted

[Josephine0110]

Fixes #12679
Fixes #12653

Outline of Solution

For Issue#12679
Added a validator to copy session component, checking whether the feedback session name is whitespace or not. If the Name for feedback session is only composed of whitespace, the red warning of "The field "Name for copied session" should not be empty." would appear on the screen.

Before: (from the issues)

After:

For Issue#12653
Modified frontend to make the user input of Course ID and Course Name mandatory by adding a red warning sign down the input box

Before:

After:

[github-actions]

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