Issue Summary

In JSW Company Managed Project settings - People -  Add people if type the user's email address, it is not checking if the user already exists on the cloud instance or not. 

This is reproducible on Data Center: (no)

Steps to Reproduce

1. Go to a JSW Project Settings - People - Add People
2. Type an email address of a user who already exists on the instance for example Faribatest@atlassian.com

Note: The same issue happens in JSW Team Managed projects Project settings - Access -  Add people

Expected Results

It should work the same as JSW and JSM projects and provide just the username because the user already exists on the cloud instance.

Actual Results

It returns two possible options:

• Faribatest
• Faribatest@atlassian.com

This is causing confusion. Also, if the user selects their own email address instead of their username it returns the following error:
We couldn't invite <email address>

If check the backend logs it generates the correct message:
"bad-request","message":"User cannot invite themselves"

Workaround

Make sure the user has granted the Browse users and groups permission in the Global permission.
Select the username not the email address unless you know the user does not exist on the instance so must be invited