Some environments might not have associated users.

There was a bug in the application settings route that threw an error if
an environment role and its associated application role did not have an
associated user. Updated to check for the user name on the application role.

tests/routes/applications/test_settings.py

@@ -1,15 +1,7 @@
 import pytest
 from flask import url_for, get_flashed_messages
 
-from tests.factories import (
-    UserFactory,
-    PortfolioFactory,
-    PortfolioRoleFactory,
-    EnvironmentRoleFactory,
-    EnvironmentFactory,
-    ApplicationFactory,
-    ApplicationRoleFactory,
-)
+from tests.factories import *
 
 from atst.domain.applications import Applications
 from atst.domain.environment_roles import EnvironmentRoles
@@ -102,7 +94,8 @@ def test_edit_application_environments_obj(app, client, user_session):
     env_role1 = EnvironmentRoleFactory.create(
         application_role=app_role1, environment=env, role=CSPRole.BASIC_ACCESS.value
     )
-    app_role2 = ApplicationRoleFactory.create(application=application)
+    app_role2 = ApplicationRoleFactory.create(application=application, user=None)
+    invite = ApplicationInvitationFactory.create(role=app_role2)
     env_role2 = EnvironmentRoleFactory.create(
         application_role=app_role2, environment=env, role=CSPRole.NETWORK_ADMIN.value
     )