fix(azure): check account_key before DefaultAzureCredential

[WangzJi]

Fix Azure Blob Storage authentication to prioritize account_key over DefaultAzureCredential

Problem Description

The WasbHook and WasbAsyncHook had an authentication priority issue where the account_key field in connection extras was being skipped when no password was provided. The hooks would directly fall back to DefaultAzureCredential without checking for account_key, causing authentication failures for users who configured their connections with account keys in the extra fields.

Solution

• Modified the authentication flow in both WasbHook.get_conn() and WasbAsyncHook.get_async_conn() to check for account_key in connection extras before falling back to DefaultAzureCredential
• Ensured proper authentication precedence following the documented behavior
• Added comprehensive test coverage for the account_key authentication method

Tests

• Added test_account_key_connection test case to verify account_key authentication works correctly
• Updated existing test parameterization to include the new connection type
• All existing tests continue to pass, ensuring backward compatibility

Changes

• hooks/wasb.py: Updated authentication logic in both sync and async hooks
• tests/test_wasb.py: Added test cases and connection setup for account_key authentication
• newsfragments/51944.bugfix.rst: Added changelog entry for the fix

Verification

This fix ensures that users can successfully authenticate using account_key in connection extras as documented in the hook's class docstring: "These parameters have to be passed in Airflow Data Base: account_name and account_key."

closes: #51944

---

^ Add meaningful description above
Read the Pull Request Guidelines for more information.
In case of fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in a newsfragment file, named {pr_number}.significant.rst or {issue_number}.significant.rst, in airflow-core/newsfragments.

[boring-cyborg]

Congratulations on your first Pull Request and welcome to the Apache Airflow community! If you have any issues or are unsure about any anything please check our Contributors' Guide (https://github.com/apache/airflow/blob/main/contributing-docs/README.rst)
Here are some useful points:

• Pay attention to the quality of your code (ruff, mypy and type annotations). Our pre-commits will help you with that.
• In case of a new feature add useful documentation (in docstrings or in docs/ directory). Adding a new operator? Check this short guide Consider adding an example DAG that shows how users should use it.
• Consider using Breeze environment for testing locally, it's a heavy docker but it ships with a working Airflow and a lot of integrations.
• Be patient and persistent. It might take some time to get a review or get the final approval from Committers.
• Please follow ASF Code of Conduct for all communication including (but not limited to) comments on Pull Requests, Mailing list and Slack.
• Be sure to read the Airflow Coding style.
• Always keep your Pull Requests rebased, otherwise your build might fail due to changes not related to your commits.
  Apache Airflow is a community-driven project and together we are making it better 🚀.
  In case of doubts contact the developers at:
  Mailing List: dev@airflow.apache.org
  Slack: https://s.apache.org/airflow-slack

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.