Users can enter the same module twice when editing profile

[nus-pe-bot]

Doesn't affect usability but perhaps a check to prevent this may improve the UI and quality of app.

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_{[original: nus-cs2103-AY2223S1/pe-interim#2321] [original labels: type.FeatureFlaw severity.VeryLow]}

[Yingming23]

Team's Response

Our design is that we want to restrict the freedom of the user too much. A user adding repeated module code to a person will not bring inconvenience to the user.

Duplicate status (if any):

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