fix: inject TRTLLM_USE_UCX_KVCACHE env var in mpirun (#4609)

deploy/cloud/operator/internal/dynamo/backend_trtllm.go

@@ -224,7 +224,7 @@ func getCommonTRTLLMEnvVars() map[string]bool {
 		"CUDA_VISIBLE_DEVICES": true, "MODEL_PATH": true, "HF_TOKEN": true, "HUGGING_FACE_HUB_TOKEN": true, "HF_ENDPOINT": true,
 		"TOKENIZERS_PARALLELISM": true, "NCCL_DEBUG": true, "NCCL_IB_DISABLE": true, "NCCL_P2P_DISABLE": true,
 		"TENSORRT_LLM_CACHE_DIR": true, "HF_HOME": true, "TRANSFORMERS_CACHE": true, "HF_DATASETS_CACHE": true,
-		"PATH": true, "LD_LIBRARY_PATH": true, "PYTHONPATH": true, "HOME": true, "USER": true,
+		"PATH": true, "LD_LIBRARY_PATH": true, "PYTHONPATH": true, "HOME": true, "USER": true, "TRTLLM_USE_UCX_KVCACHE": true,
 	}
 }