ContainerPushRepository.DoesNotExist exception raised when trying to push to a "regular" repo with the same name

[git-hyagi]

Describe the bug
Trying to push a container image with the name of a repository previously created will raise an exception:

Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "/usr/local/lib/python3.9/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/usr/local/lib/python3.9/site-packages/django/views/decorators/csrf.py", line 56, in wrapper_view
    return view_func(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/viewsets.py", line 124, in view
    return self.dispatch(request, *args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "/src/pulp_container/pulp_container/app/registry_api.py", line 279, in handle_exception
    response = super().handle_exception(exc)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py", line 480, in raise_uncaught_exception
    raise exc
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "/src/pulp_container/pulp_container/app/registry_api.py", line 764, in create
    _, repository = self.get_dr_push(request, path, create=True)
  File "/src/pulp_container/pulp_container/app/registry_api.py", line 373, in get_dr_push
    distribution, repository = self.create_dr(path, request)
  File "/src/pulp_container/pulp_container/app/registry_api.py", line 395, in create_dr
    repository = serializers.ContainerPushRepositorySerializer.get_or_create({"name": path})
  File "/src/pulpcore/pulpcore/app/serializers/base.py", line 383, in get_or_create
    result = cls.Meta.model.objects.get(**natural_key)
  File "/usr/local/lib/python3.9/site-packages/django/db/models/manager.py", line 87, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/django/db/models/query.py", line 637, in get
    raise self.model.DoesNotExist(
pulp_container.app.models.ContainerPushRepository.DoesNotExist: ContainerPushRepository matching query does not exist.
('pulp [26bd665793b340718baea475f1f2a149]: ::ffff:127.0.0.1 - admin [24/Jul/2024:17:58:25 +0000] "POST /v2/test/blobs/uploads/ HTTP/1.0" 500 145 "-" "containers/5.29.2 (github.com/containers/image)"',)

To Reproduce
Steps to reproduce the behavior:

• create a new "regular" (non push) repository

pulp container repository create --name test

• try to push an image with the same name as the repository:

$ podman push ce55fc75798a pulp-container:5001/test:latest
Getting image source signatures
Copying blob 20dd87a4c2ab [--------------------------------------] 8.0b / 99.0MiB | 2.0 MiB/s
...
Error: writing blob: initiating layer upload to /v2/test/blobs/uploads/ in pulp-container:5001: received unexpected HTTP status: 500 Internal Server Error

Expected behavior
Instead of raising an exception we could handle the error and provide a better output.