Access tokens that contains '@' are not visible in the UI

In case that we are creating access tokens with users that contain '@' we will not be able to view the tokens in the UI.

Steps to reproduce
1. Create a user with @ like the following example:
batel@jfrog.com
2. Create an access token with this user for example:

curl -ubatel@jfrog.com -XPOST "http://localhost:8081/artifactory/api/security/token" -d "username=test" -d "scope=member-of-groups:readers" -d "expires_in=0"

3. Check the access tokens via the UI