Bug with adding person with duplicate emails

[nus-pe-bot]

Steps to reproduce:

1. add n/John p/87438807 e/alexyeoh@example.com a/Blk 30 Geylang Street 29
2. add n/Doe p/87438807 e/alexyeoh@example.com a/Blk 30 Geylang Street 29

Expected:
Error message as duplicate emails should not be allowed

Actual:
Command is accepted and duplicate emails are shown in the UI.

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_{[original: nus-cs2103-AY2324S2/pe-interim#1944] [original labels: severity.Low type.FeatureFlaw]}

[Tanzhiheng26]

Team's Response

No details provided by team.

Duplicate status (if any):

Duplicate of #5577