CI test linux://rllib:learning_tests_multi_agent_pong_appo_multi_gpu is flaky

[can-anyscale]

CI test linux://rllib:learning_tests_multi_agent_pong_appo_multi_gpu is flaky. Recent failures:
- https://buildkite.com/ray-project/postmerge/builds/13677#0199e185-0a21-482c-99d6-81fa74297bfa
- https://buildkite.com/ray-project/postmerge/builds/13671#0199e08b-ec26-4005-90bf-2334d11ea4d8
- https://buildkite.com/ray-project/postmerge/builds/13584#0199c7ba-d477-410d-9d0b-254c7fcca7d7

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

[can-anyscale]

Test passed on latest run: https://buildkite.com/ray-project/postmerge/builds/13727#0199e9f5-f5be-43e8-8233-3a4ed2e50876