When using ADC with BigQuery DataSources, the Test Connection behaves strangely

[as-cyrill]

Issue Summary

Move from oauth2client to google-auth / support ADC #6422

The above Pull Request supports Application Default Credentials (ADC), but when trying to access BigQuery using Workloads Identity, an incorrect message is displayed during the Test Connection.

Steps to Reproduce

1. To use ADC, set the environment variable GOOGLE_APPLICATION_CREDENTIALS.
2. Set the Name and Project ID.
3. Press the TEST Connection button.

Expected Behavior

Connection Test Success

Actual Behavior

Connection Test Failed:
Service account info was not in the expected format, missing fields token_uri, client_email.

It seems that the Test Connection checks the format of the service account JSON file and verifies the existence of token_uri and client_email. However, when using ADC, these keys do not exist, causing the test to fail even though the connection actually succeeds.

Technical details:

• Redash Version: 25.1.0
• Browser/OS: Any
• How did you install Redash: Container on EKS