remove custom manager on user

opus_submitter/accounts/models.py

@@ -2,14 +2,6 @@ from django.contrib.auth.models import AbstractUser
 from django.db import models
 
 
-class UserQuerySet(models.QuerySet):
-    pass
-
-
-class UserManager(models.Manager.from_queryset(UserQuerySet)):
-    pass
-
-
 class CustomUser(AbstractUser):
     """Custom User model to store CAS attributes from PolyLAN."""
 
@@ -22,11 +14,6 @@ class CustomUser(AbstractUser):
     # Additional fields that might come from CAS
     cas_attributes = models.JSONField(default=dict, blank=True)
 
-    objects = UserManager()
-
-    class Meta:
-        _base_manager_name = "objects"
-
     def __str__(self):
         return f"{self.username} ({self.cas_user_id})"