refactor(assistance): Update all references to User to use get_user_model()

ref: #754 #755

app/assistance/models/knowledge_base.py

@@ -1,4 +1,4 @@
-from django.contrib.auth.models import User
+import django
 from django.db import models
 from django.forms import ValidationError
 
@@ -6,6 +6,9 @@ from access.fields import *
 from access.models.team import Team
 from access.models.tenancy import TenancyObject
 
+User = django.contrib.auth.get_user_model()
+
+
 
 class KnowledgeBaseCategory(TenancyObject):