Add Configuration Option to Disable Async Token Refresh

[emmyzhou-db]

What changes are proposed in this pull request?

This PR adds a new configuration option to control asynchronous token refresh behavior in the Databricks SDK for Java.

Changes

• Added disableAsyncTokenRefresh configuration to DatabricksConfig with environment variable DATABRICKS_DISABLE_ASYNC_TOKEN_REFRESH
• Async token refresh is enabled by default for optimal performance

To disable async token refresh

Environment Variable:

export DATABRICKS_DISABLE_ASYNC_TOKEN_REFRESH=true

Programmatic:

DatabricksConfig config = new DatabricksConfig()
    .setDisableAsyncTokenRefresh(true);

How is this tested?

Existing unit and integration tests.

[github-actions]

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Trigger:
go/deco-tests-run/sdk-java

Inputs:

• PR number: 478
• Commit SHA: 70e576c582cc3e5460252ee6f980537cde2d33dc

Checks will be approved automatically on success.