[None][chore] Add failed cases into waives.txt (#6914)

Signed-off-by: xinhe-nv <[email protected]>

Author: xinhe-nv

tests/integration/test_lists/waives.txt

@@ -318,3 +318,5 @@ triton_server/test_triton.py::test_mistral_ib_mm[mistral-ib-mm] SKIP (https://nv
 triton_server/test_triton.py::test_t5_ib[t5-ib] SKIP (https://nvbugs/5456482)
 triton_server/test_triton_llm.py::test_gpt_speculative_decoding_bls[False-False-1---False-True-True-0-128-disableDecoupleMode-inflight_fused_batching-disableTrtOverlap-0.2-guaranteed_no_evict---1-1-1-False-ensemble] SKIP (https://nvbugs/5456485)
 accuracy/test_disaggregated_serving.py::TestLlama3_1_8BInstruct::test_ctx_pp_gen_tp_asymmetric[GSM8K-gen_tp=1-ctx_pp=4] SKIP (https://nvbugs/5434320)
+accuracy/test_disaggregated_serving.py::TestQwen3_8B::test_nixl_backend SKIP (https://nvbugs/5448437)
+accuracy/test_disaggregated_serving.py::TestDeepSeekV3Lite::test_nixl_backend SKIP (https://nvbugs/5448437)