[nvbugs/5401261][fix] Fix Triton backend disaggregated serving support (#6224)

Signed-off-by: Iman Tabrizian <[email protected]>

Author: Tabrizian

tests/integration/test_lists/waives.txt

@@ -427,8 +427,6 @@ test_e2e.py::test_ptp_quickstart_multimodal[gemma-3-27b-it-gemma/gemma-3-27b-it-
 accuracy/test_llm_api_pytorch.py::TestQwen3_30B_A3B::test_nvfp4[dep4_latency_moe_trtllm] SKIP (https://nvbugs/5401163)
 accuracy/test_llm_api_pytorch.py::TestQwen3_30B_A3B::test_nvfp4[tep4_latency_moe_trtllm] SKIP (https://nvbugs/5401163)
 examples/test_recurrentgemma.py::test_llm_recurrentgemma_1gpu[use_cpp_session-recurrentgemma-2b-use_paged_cache-int4_awq-float16-enable_attn_plugin-enable_gemm_plugin] SKIP (https://nvbugs/5401233)
-triton_server/test_triton_llm.py::test_gpt_disaggregated_serving_bls[test_basic-False-1-top_k_top_p--False-True-True-0-128-enableDecoupleMode-inflight_fused_batching-disableTrtOverlap-0.2-max_utilization---1-1-1-True-tensorrt_llm_bls] SKIP (https://nvbugs/5401261)
-triton_server/test_triton.py::test_gpt_disaggregated_serving_bls[gpt-disaggregated-serving-bls] SKIP (https://nvbugs/5401261)
 examples/test_recurrentgemma.py::test_llm_recurrentgemma_2gpu[recurrentgemma-2b] SKIP (https://nvbugs/5401233)
 examples/test_multimodal.py::test_llm_multimodal_general[VILA1.5-3b-pp:1-tp:1-float16-bs:1-cpp_e2e:False-nb:1] SKIP (https://nvbugs/5401156)
 test_e2e.py::test_ptp_quickstart_multimodal[mistral-small-3.1-24b-instruct-Mistral-Small-3.1-24B-Instruct-2503-image-True] SKIP (https://nvbugs/5404005)

triton_backend/inflight_batcher_llm/src/model_instance_state.cc

@@ -698,6 +698,7 @@ executor::ExecutorConfig ModelInstanceState::getExecutorConfigFromParams()
         maxQueueSize, extendedRuntimePerfKnobConfig,
         /*DebugConfig*/ std::nullopt, recvPollPeriodMs};
     execConfig.setSpecDecConfig(specDecConfig);
+    execConfig.setCacheTransceiverConfig(tle::CacheTransceiverConfig(tle::CacheTransceiverConfig::BackendType::MPI));
     if (guidedConfig.has_value())
     {
         execConfig.setGuidedDecodingConfig(guidedConfig.value());