API - Store subscribers cannot accept '+' symbols in email (bug)

[yewzy]

When a POST request is sent to store subscribers with emails including the character '+', eg. ( [email protected]), the error response is "The email must be a valid email address.".

This is a common way for gmail users to create alias for their account. (https://www.techadvisory.org/2014/08/using-an-alias-in-gmail/)