fix: Unregisters Group from admin panel

Removes Group model from the Django admin interface to simplify admin
views and focus on custom registration logic. This cleanup aids in
preventing unnecessary admin clutter, ensuring the admin interface
aligns with project-specific needs.

Improves admin interface customization and usability.

src/synapse_registration/registration/admin.py

@@ -1,9 +1,12 @@
 from django.contrib import admin
+from django.contrib.auth.models import Group
 
 from .models import UserRegistration
 
 admin.site.site_header = "Synapse Registration Administration"
 
+admin.site.unregister(Group)
+
 
 @admin.register(UserRegistration)
 class UserRegistrationAdmin(admin.ModelAdmin):
@@ -16,7 +19,7 @@ class UserRegistrationAdmin(admin.ModelAdmin):
         for registration in queryset:
             registration.status = UserRegistration.STATUS_APPROVED
             registration.save()
-            
+
         self.message_user(request, f"{queryset.count()} registrations approved.")
 
     def deny_registrations(self, request, queryset):