[Bugfix] treewide: drop references to librosa (#2996)

Signed-off-by: Nick Cao <ncao@redhat.com>

tests/model_executor/models/voxcpm2/test_talker_state_eviction.py

@@ -7,7 +7,6 @@ from __future__ import annotations
 import pytest
 
 torch = pytest.importorskip("torch")
-pytest.importorskip("librosa")
 
 from vllm_omni.model_executor.models.voxcpm2.voxcpm2_talker import (  # noqa: E402
     VoxCPM2TalkerForConditionalGeneration,