No duplicate detection for phone number

[nus-se-script]

There is no duplication check for the phone number and will not show any message if the newly added person shares a same phone number as any of the existing people. In reality, usually it is not possible for 2 people sharing the same number and this is very likely caused by a typo, which a confirmation message or error message is recommended to be displayed.

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_{[original: nus-cs2103-AY2324S1/pe-interim#1024] [original labels: severity.Low type.FeatureFlaw]}

[freshcabbage123]

Team's Response

Following similar reasoning, it is very likely in the real world for 2 people to share the same numbers i.e. colleagues in the same department sharing a common office number.

Duplicate status (if any):

Duplicate of #5148