Not possible to add users to Project permissions if they don't have the Bitbucket users permission

Summary

On current versions of Bitbucket Server (4.0+), it's not possible to give project permissions to users in Bitbucket, if they don't have the "Bitbucket users" global permission

This feature used to work on Stash 3.3.2, and this is the current behaviour on JIRA

Steps to Reproduce

1. On the project permissions page, try adding a LDAP user which does not have at least 'Bitbucket User' global permissions

Expected Results

The LDAP user should be appear in the dropdown and it's possible to add them in the project permissions

Actual Results

The LDAP user doesn't appear in the dropdown and it's not possible to add them in the project permissions