[PULP-2500] Deactivate local DistributedPublication in favour of pulpcore's

[pedro-psb]

This deactivates the use of DistributedPublication, as the content app is already using pulpcore's version effectively. It doesn't remove the tables (yet) to ensure zero-downtime-upgrades don't fail. That should be done in a future commit/release.

Closes: #1430
Assisted-by: GPT-6-Luna

📜 Checklist

• Commits are cleanly separated with meaningful messages (simple features and bug fixes should be squashed to one commit)
• A changelog entry or entries has been added for any significant changes
• Follows the Pulp policy on AI Usage
• (For new features) - User documentation and test coverage has been added

See: Pull Request Walkthrough

[pedro-psb]

This doesnt add new functional test, because the existing tests for distributed content should just keep working:

pulp_deb/pulp_deb/tests/functional/api/test_download_content.py

Lines 179 to 209 in e3a91d7

	def test_download_cached_content(
	deb_init_and_sync,
	deb_distribution_factory,
	deb_publication_factory,
	deb_fixture_server,
	download_content_unit,
	http_get,
	deb_get_content_types,
	deb_modify_repository,
	):
	"""Verify that previously published content can still be downloaded."""
	# Create/sync a repo and then a distro
	repo, _ = deb_init_and_sync()
	distribution = deb_distribution_factory(repository=repo)
	deb_publication_factory(repo, structured=True, simple=True)
	# Find a random package and get its hash digest
	package_content = deb_get_content_types("apt_package_api", DEB_PACKAGE_NAME, repo)
	package = choice(package_content)
	url = deb_fixture_server.make_url(DEB_FIXTURE_STANDARD_REPOSITORY_NAME)
	package_hash = hashlib.sha256(http_get(urljoin(url, package.relative_path))).hexdigest()
	# Remove content and republish
	deb_modify_repository(repo, {"remove_content_units": ["*"]})
	deb_publication_factory(repo, structured=True, simple=True)
	# Download the package and check its checksum
	content = download_content_unit(distribution.base_path, package.relative_path)
	content_hash = hashlib.sha256(content).hexdigest()
	assert package_hash == content_hash

[quba42]

Given this is a follow up/cleanup task for #925, the tests have remained green, I trust those involved, and I also don't use this feature myself, I am tempted to wave this through.

However, before I do, I would like to give the original contributor of the original change @daviddavis, as well as his teammate @acheng-01 (whom it is my understanding has inherited David's role from then) a chance to weigh in.

Do either of you want to review this before I end up simply approving and merging it?

[acheng-01]

Given this is a follow up/cleanup task for #925, the tests have remained green, I trust those involved, and I also don't use this feature myself, I am tempted to wave this through.

However, before I do, I would like to give the original contributor of the original change @daviddavis, as well as his teammate @acheng-01 (whom it is my understanding has inherited David's role from then) a chance to weigh in.

Do either of you want to review this before I end up simply approving and merging it?

Give me today to review for any potential breaking issues on our end. I'll report back in a bit.

[acheng-01]

Relatively low-risk upgrade path.

[pedro-psb]

Thanks for the review.
I'll just update the test to be skipped then.