funasr_onnx: Fsmn_vad_online raises UnboundLocalError when a chunk produces no feature frames (e.g. 10-30 ms chunks) #3821

Fsmn_vad_online.__call__ (runtime/python/onnxruntime/funasr_onnx/vad_bin.py) assigns vad_scorer only inside if feats.size != 0:, but always runs param_dict.update({"frontend": frontend, "vad_scorer": vad_scorer}) afterwards. When WavFrontendOnline.extract_fbank returns no feature frames for a call, it raises:

UnboundLocalError: cannot access local variable 'vad_scorer' where it is not associated with a value

This happens on the first call when the first chunk is shorter than 720 samples (45 ms at 16 kHz), so streaming 10, 20 or 30 ms chunks fails at once. It also happens on a later call whose chunk completes no new feature frame, for example a 40-sample packet after 100 ms chunks. The README's 100 ms chunks are not affected, and the failing path never reaches the ONNX session.

Repro: run the streaming example for Fsmn_vad_online with step = 320 (20 ms) instead of 1600. The first model(audio_in=..., param_dict=param_dict) call raises the error above.

It came in with #2528, which moved the scorer into param_dict; before that, a call without features returned [].