Fall back for empty console domain

[suyua9]

What changed

Treat an empty GOOGLE_CLOUD_HIGH_VALUE_COOKIE_DOMAIN value as the default google.com domain. This prevents the Google provider's sovereign-console link helpers from emitting https://console.cloud. when the variable is present but empty.

The change adds direct coverage for unset, empty, and custom values.

Tests

• ruff format --check (changed files)
• ruff check (changed files)
• python3 -m compileall (changed files)
• Targeted pytest was attempted with the repository-required uv 0.11.8, but dependency resolution could not build pykerberos because this machine's xcrun Command Line Tools library has an architecture mismatch. GitHub CI should run the added test in the project toolchain.

---

Was generative AI tooling used to co-author this PR?

• Yes (Codex)

[SameerMesiah97]

Just one nit. Also, fix the commit message as that is causing CI to fail.

[SameerMesiah97]

This works but it could be clearer. Please see the below:

domain = os.getenv("GOOGLE_CLOUD_HIGH_VALUE_COOKIE_DOMAIN")
return "google.com" if domain in (None, "") else domain

[suyua9]

Addressed the review feedback and refreshed the branch onto the current main:

• read the environment value into a local domain variable before handling the unset/empty fallback;
• retained the existing unset, empty, and custom-value regression coverage;
• changed the PR title to the repository-required non-Conventional-Commits form.

Validation run:

• git diff --check
• ruff format --check providers/google/src/airflow/providers/google/common/hooks/base_google.py
• ruff check providers/google/src/airflow/providers/google/common/hooks/base_google.py
• python3 -m compileall -q providers/google/src/airflow/providers/google/common/hooks/base_google.py

The targeted pytest command could not run locally because this checkout requires uv >=0.11.8 while the installed version is 0.10.8; CI will cover the existing targeted regression test.