CI test linux://rllib:learning_tests_stateless_cartpole_appo_gpu is flaky

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CI test linux://rllib:learning_tests_stateless_cartpole_appo_gpu is consistently_failing. Recent failures:
- https://buildkite.com/ray-project/postmerge/builds/5988#01917dee-3809-42ec-a9e8-f2050d1f2f6f
- https://buildkite.com/ray-project/postmerge/builds/5988#01917da0-6544-43ff-bcbd-e7d265169c1f

DataCaseName-linux://rllib:learning_tests_stateless_cartpole_appo_gpu-END
Managed by OSS Test Policy

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Blamed commit: 6743d3d found by bisect job https://buildkite.com/ray-project/release-tests-bisect/builds/1482

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Test passed on latest run: https://buildkite.com/ray-project/postmerge/builds/5991#01917ffd-f45f-4216-9264-c1634e9cf23f

[can-anyscale]

new added + flaky tests