Add an option to set a timeout for browser confirmation in the U2M authentication flow.

[renaudhartert-db]

What changes are proposed in this pull request?

This PR adds a configurable timeout for OAuth browser authentication in the Databricks SDK for Java.

The OAuth browser authentication flow currently waits indefinitely for user interaction, which can cause applications to hang indefinitely if users don't complete the authentication process.

The key changes include:

• New configuration option: Added setOAuthBrowserAuthTimeout(Duration timeout) to DatabricksConfig with environment variable support via DATABRICKS_OAUTH_BROWSER_AUTH_TIMEOUT.
• Timeout implementation: Modified the OAuth consent flow in Consent.CallbackResponseHandler to enforce the configured timeout when waiting for browser callback parameters.
• Bug fixes: Fixed ConfigAttributeAccessor to properly handle Duration, Integer, and Boolean types from environment variables.

How is this tested?

Added unit tests to verify that env variables are properly loaded and that the timeout logic works as expected.

[github-actions]

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Trigger:
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Inputs:

• PR number: 496
• Commit SHA: 3a54783be4f67538a6221d2923784f378d839b46

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