[core] Tune timeout to reduce run time of test_transient_error_retry

[edoakes]

The test times out frequently in CI.

Before this change, the test took ~40s to run on my laptop. After the change, the test took ~15s to run on my laptop.

[gemini-code-assist]

Code Review

This pull request aims to reduce the runtime of test_transient_error_retry to prevent CI timeouts. The changes achieve this by tuning RAY_actor_scheduling_queue_max_reorder_wait_seconds to a lower value. Additionally, the test is simplified by removing an unnecessary resource constraint (resources={"head": 1}) for the actor and the worker node. The changes look good and effectively address the performance issue with the test. I have one minor suggestion to add a comment explaining the purpose of the environment variable for better maintainability.