[PE-D][Tester D] Nitpick: inaccurate error message for incorrect NRIC entered for add_p command

[nus-se-script]

Steps I took:

1. Entered "add_p n\legolas ic\T123456789Z p\987654321"

Perhaps a message like "NRIC should only contain alphanumeric characters in this format: XYYYYYYYX where X is an alphabet and Y is a number and it should not be blank" would be more specific for this kind of error :)

Expected: A more specific error message since the entered value technically adheres to the given requirement. Actual:

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Labels: severity.VeryLow type.FunctionalityBug original: sopa301/ped#2

[derekjxtan]

same as #225