[CI/Build] Clean up Qwen3-Omni nightly tests (#6570)

Signed-off-by: psv666 <2693925048@qq.com>

tests/dfx/reliability/invalid_param_test/test_invalid_omni_chat.py

@@ -72,6 +72,9 @@ def _chat_completions_request_without_expectations(omni_server: OmniServer, case
         body["top_logprobs"] = 5
     elif case_id == "speaker_unknown":
         body["speaker"] = "zz_invalid_qwen3_omni_chat_speaker_xyz"
+    elif case_id == "audio_format_unsupported":
+        body["modalities"] = ["text", "audio"]
+        body["audio"] = {"voice": "alloy", "format": "aac"}
     else:
         raise AssertionError(f"unknown chat completions invalid case_id {case_id!r}")
     return {"json": body, "timeout": 120}
@@ -135,6 +138,12 @@ def _chat_completions_request_without_expectations(omni_server: OmniServer, case
             ("Invalid speaker", "Supported"),
             id="speaker_unknown_preset",
         ),
+        pytest.param(
+            "audio_format_unsupported",
+            400,
+            ("Invalid audio format", "aac", "Supported formats"),
+            id="unsupported_audio_format",
+        ),
     ],
 )
 @pytest.mark.parametrize("omni_server", _QWEN3_OMNI_SERVER, indirect=True)