[Refactor] Remove dependency on librosa (#2273)

Signed-off-by: Nick Cao <ncao@redhat.com>
Co-authored-by: Claude <noreply@anthropic.com>

docs/user_guide/examples/online_serving/bagel.md

@@ -357,13 +357,6 @@ curl http://localhost:8091/v1/chat/completions \
 
 ## FAQ
 
-- If you encounter an error about the backend of librosa, try to install ffmpeg with the command below.
-
-```bash
-sudo apt update
-sudo apt install ffmpeg
-```
-
 - If you don’t know how much VRAM is needed for the model or encounter the OOM error, you can try to decrease the max_model_len.
 
 | Stage               | VRAM                         |