[Tests] backcompat test_managed_jobs is flaky for kubernetes

[kyuds]

pytest tests/smoke_tests/backward_compat/test_backward_compat.py::TestBackwardCompatibility::test_managed_jobs --kubernetes --base-branch master

is failing 3/4. Seems to be due to a timeout issue
https://buildkite.com/skypilot-1/quicktest-core/builds/1713

[kyuds]

actually no longer flaky. Think it was a k8s issue during that time period.