Flake in `run_compute_errors()` test

[github-actions]

Failure in Google Cloud Build on main:

• Build: gcb-pm-integration-unstable (rust-sdk-testing)
• Build Log: https://console.cloud.google.com/cloud-build/builds;region=us-central1/96795caf-d30a-4eb1-a7e8-ffc1fc236812?project=1044885715437
• Commit: d2d73bf

Associated Pull Requests:

• cleanup(gax-internal): features and links #5972

[github-actions]

@googleapis/cloud-sdk-rust-team A critical issue has been created, please respond immediately.

[coryan]

Hmmm... a timeout on a GET call, the default retry policy does not work well for this test.

Let me disable it first.