Fix incorrect model type check in process_frame method

Signed-off-by: He Huang (Steve) <105218074+stevehuang52@users.noreply.github.com>

Author: stevehuang52

nemo/agents/voice_agent/pipecat/services/nemo/stt.py

@@ -34,7 +34,6 @@
 from pydantic import BaseModel
 
 from nemo.agents.voice_agent.pipecat.services.nemo.streaming_asr import NemoStreamingASRService
-from nemo.agents.voice_agent.pipecat.services.nemo.streaming_diar import NeMoStreamingDiarService
 
 try:
     # disable nemo logging
@@ -267,7 +266,7 @@ async def set_model(self, model: str):
 
     async def process_frame(self, frame: Frame, direction: FrameDirection):
         """Process incoming frames and handle VAD events."""
-        if isinstance(frame, VADUserStoppedSpeakingFrame) and isinstance(self._model, NeMoStreamingDiarService):
+        if isinstance(frame, VADUserStoppedSpeakingFrame) and isinstance(self._model, NemoStreamingASRService):
             # manualy reset the state of the model when end of utterance is detected by VAD
             logger.debug("Resetting state of the model due to VADUserStoppedSpeakingFrame")
             self._model.reset_state()