chore: complete google-cloud-dns migration

[jskeet]

• Reformat with nox
• Enable generation with librarian
• Regenerate with librarian

[gemini-code-assist]

Code Review

This pull request updates the configuration and metadata for the google-cloud-dns package, including enabling generation in librarian.yaml and cleaning up .repo-metadata.json. It also performs extensive linting and import reordering across the codebase to improve consistency. A review comment suggests restoring a blank line between third-party and local imports in _http.py to adhere to PEP 8 standards.

[gemini-code-assist]

According to PEP 8, there should be a blank line between related third-party imports and local application-specific imports. google.cloud._http is a dependency from google-cloud-core, while google.cloud.dns is part of the local package. This consistency is maintained in other files like changes.py and zone.py but was removed here.

Suggested change

	from google.cloud import _http
	from google.cloud.dns import __version__
	from google.cloud import _http
	from google.cloud.dns import __version__

References

1. PEP 8 recommends grouping imports: standard library, third-party, and local application imports, with a blank line between each group. ^(link)

[parthea]

The import error is due to the __version__ being moved

The Execution Chain
__init__.py starts. It reaches line 27: from google.cloud.dns.client import Client.

client.py starts. It reaches line 21: from google.cloud.dns._http import Connection.

_http.py starts. It reaches line 18: from google.cloud.dns import __version__.

Back to __init__.py: Python looks for __version__ in google.cloud.dns. However, because __init__.py is still waiting for Client to finish loading, it hasn't reached the line where __version__ is defined yet. Crash.

Restoring the original code fixes the error

# 1. Define/Import the version FIRST
from google.cloud.dns.version import __version__

You can see a similar pattern in the generated clients were we have __version__ at the top

google-cloud-python/packages/google-cloud-access-approval/google/cloud/accessapproval_v1/__init__.py

Lines 20 to 22 in c422cbb

	from google.cloud.accessapproval_v1 import gapic_version as package_version
	__version__ = package_version.__version__