title: Error with inlined profile form save in django admin
body: <p>I really confised, because problem sounds trivial, but I didn't googled anything related to this. I found one very simular question <a href="https://stackoverflow.com/questions/56465018/django-admin-create-form-inline-onetoone">Django Admin Create Form Inline OneToOne</a> but in my case I cannot remove signal, it'll break normal way of user creation in my app.
  I have model User and Profile connected OneToOne relationship (models.py):</p>
  
  <pre><code>from django.db import models
  from django.contrib.auth.models import AbstractUser
  
  from django.db.models.signals import post_save, pre_save
  from django.dispatch import receiver
  from .managers import UserManager
  
  class User(AbstractUser):
      """auth/login-related fields"""
      username = None
      email = models.EmailField(unique=True)
      USERNAME_FIELD = 'email'
      REQUIRED_FIELDS = []
      objects = UserManager()
  
      def __str__(self):
          return self.email 
  
  class Profile(models.Model):
      """profile fields"""
      user = models.OneToOneField(User, on_delete=models.CASCADE)
      about = models.CharField(max_length=2000, blank=True)
      telegram = models.CharField(max_length=25, blank=True)
      def save(self, *args, **kwargs):
          print('save profile', args, kwargs) # from admin it run 2 times, second with empty args, kwargs so PROBLEM HERE!!!
          print('save profile complete')
  
  """receivers to add a Profile for newly created users"""
  @receiver(post_save, sender=User) 
  def create_user_profile(sender, instance, created, **kwargs):
      print('create_user_profile', created, instance.id)
      if created:
          try:
              p = Profile.objects.create(user = instance)
              print('succsecc!!!!', p, p.id) ## here profile object created and got id
          except Exception as e:
              print('create profile error', e) # never prints
      else:
          instance.profile.save()
  
  """ @receiver(post_save, sender=User) 
  def save_user_profile(sender, instance, **kwargs):
      print('save_user_profile')
      try:
          instance.profile.save()
      except Exception:
              print('save profile error', Exception)
   """
  </code></pre>
  
  <p>This models works well from frontend of my application, users register and fill their profiles, everything OK.
  Problem occur when I try to make user from django admin. Then I getting <code>django.db.utils.IntegrityError: UNIQUE constraint failed: authenticate_profile.user_id.</code></p>
  
  <p>My admin.py file looks like this:</p>
  
  <pre><code>from django.contrib import admin
  from django.contrib.auth.models import Group
  
  from django.contrib.auth.admin import UserAdmin
  from django.contrib.auth.forms import UserCreationForm, UserChangeForm, ReadOnlyPasswordHashField
  from django import forms
  
  from django.contrib.auth import get_user_model
  from .models import Profile
  from .forms import SignUpForm
  
  User = get_user_model()
  
  class UserInline(admin.StackedInline):
      model = Profile
      can_delete = True
      verbose_name = Profile
  
      def save_model(self, request, obj, form, change):
          print('save_model profile', request.POST, obj, form, change) ## never prints
          super().save_model(request, obj, form, change)    
  
  class CustomUserAdmin(UserAdmin):
      add_form = SignUpForm
      form = UserChangeForm
      model = User
      list_display = ('email', 'first_name', 'last_name', 'is_staff', 'is_active',)
      list_filter = ('email', 'first_name', 'last_name', 'is_staff', 'is_active',)
      fieldsets = (
          (None, {'fields': ('email', 'first_name', 'last_name' 'password1', 'password2')}),
          ('Permissions', {'fields': ('is_staff', 'is_active')}),
      )
      add_fieldsets = (
          (None, {
              'classes': ('wide',),
              'fields': ('email', 'first_name', 'last_name', 'password1', 'password2', 'is_staff', 'is_active')}
          ),
      )
      search_fields = ('email',)
      ordering = ('email',)
      inlines = (UserInline, )
  
      def save_model(self, request, obj, form, change):
          print('save_model user', request.POST, obj, form, change)
          super().save_model(request, obj, form, change)
  
  
  
  admin.site.register(User, CustomUserAdmin)
  </code></pre>
  
  <p>Code in post_save signal successfully runs, and creates profile, after that  django tries to save profile from inlined form, and fails with this error <code>django.db.utils.IntegrityError: UNIQUE constraint failed authenticate_profile.user_id</code>. From logs I see, Profile.save(), when I create user from admin, called twice, second time without args and kwargs. But when I override save method of profile model, not to run <code>super().save()</code> without arguments, I have no errors, but I unable to save profile both from admin and frontend. So problem lies in this method - HOW TO OVERRIDE IT TO WORK BOTH FROM ADMIN AND NORMAL WORKFLOW?. Thanks in advance!</p>