feat: use profile name in navbar if available

Makes use of name field from user profile field if it is not empty

lms/templates/header/user_dropdown.html

@@ -19,7 +19,9 @@
 self.real_user = getattr(user, 'real_user', user)
 profile_image_url = get_profile_image_urls_for_user(self.real_user)['medium']
 username = self.real_user.username
-displayname = get_enterprise_learner_generic_name(request) or username
+profile = getattr(self.real_user, 'profile', None)
+name = getattr(profile, 'name', username)
+displayname = get_enterprise_learner_generic_name(request) or name
 enterprise_customer_portal = get_enterprise_learner_portal(request)
 ## Enterprises with the learner portal enabled should not show order history, as it does
 ## not apply to the learner's method of purchasing content.