When admin sets default project limit to 0, it's not ideal that users receive the warning banner

Zendesk issue: https://gitlab.zendesk.com/agent/tickets/15036 Related to the feature that was merged from https://github.com/gitlabhq/gitlabhq/pull/9876

Some organizations do not want users to have personal projects in GitLab. They set the default project limit to 0. Users are able to create projects within the proper groups depending on their membership. In this case it's confusing users for users to see the message about reaching the project limit and they are asking the admin what the problem is. Would it be more appropriate to put this notification in the new project page if a user selects their namespace?

cc/ @stanhu (Mentioning you since you reviewed the original feature)

cc/ @dzaporozhets Thoughts?