feat(subprocess_server): add fallback to Google Maven mirror

[liferoad]

Implement fallback mechanism to use Google Maven mirror when downloads from Maven Central fail (e.g. 403 Forbidden). This improves reliability of jar downloads by providing an alternative source.

Addresses #36338

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[gemini-code-assist]

Summary of Changes

Hello @liferoad, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a critical reliability enhancement for the subprocess_server by adding a fallback mechanism for Java JAR downloads. When attempts to fetch JARs from Maven Central encounter errors, such as a 403 Forbidden response, the system will now automatically try to download the required JARs from the Google Maven mirror. This change significantly improves the robustness of dependency resolution, ensuring that the system can continue to function even if the primary Maven Central repository experiences issues.

Highlights

• Maven Download Fallback: Implemented a fallback mechanism to use the Google Maven mirror for JAR downloads when requests to Maven Central fail, specifically addressing 403 Forbidden errors.
• Enhanced Reliability: Improves the reliability of JAR dependency resolution by providing an alternative download source, ensuring smoother operation even with intermittent Maven Central issues.
• New Test Case: Added a new unit test to subprocess_server_test.py that verifies the Google Maven mirror fallback functionality by simulating a Maven Central failure.

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[damccorm]

Thanks!

[github-actions]

Checks are failing. Will not request review until checks are succeeding. If you'd like to override that behavior, comment assign set of reviewers

[Abacn]

Thank you!

[liferoad]

failed workflows are not related to this PR.