#5760 work email is not validated for uniqueness when hiring

[Chamila Madusani]

Module: Recruitment

Description:
1. Assume that employee Kayla's Email address is saved in the system as kayla@orangehrm.com
2. now add a candidate (from the system or web page) with the email address as kayla@orangehrm.com > system allows to save.
3. now hire the added candidate
4. go to PIM > Contact Details tab of the hired candidate and try to edit and save > system allows to save.

Better to validate the email address at the time of adding the candidate from the system or web page/RSS feed.