We changed the way flag was passed in this PR: https://github.com/grpc/psm-interop/pull/94
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Closes#36827
COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/36827 from XuanWang-Amos:csm_fix_interop a2c2c47f30
PiperOrigin-RevId: 640908453
14d76aac59