[Model] Add Voxtral TTS model (#1803)

Signed-off-by: Chen-Yo Sun <chenyo.sun@mistral.ai>

tests/conftest.py

@@ -1236,8 +1236,6 @@ def omni_server(request: pytest.FixtureRequest, run_level: str, model_prefix: st
         port = params.port
         stage_config_path = params.stage_config_path
         if run_level == "advanced_model" and stage_config_path is not None:
-            # Dynamically detect stages from config to avoid KeyError
-            # for models with fewer stages (e.g., BAGEL has 2, Qwen3-Omni has 3)
             with open(stage_config_path, encoding="utf-8") as f:
                 _cfg = yaml.safe_load(f) or {}
             _stage_ids = [s["stage_id"] for s in _cfg.get("stage_args", []) if "stage_id" in s]