Make it so that AIService is the exclusive "syncer" of model name to metrics.

The only (rare) exception—where a service directly still needs to directly call `self._sync_model_name_to_metrics()`—is when the model name need to be "pulled" from another field (or nested field) in settings up to settings.model on a settings update. This only occurs in Deepgram services, where we use the voice as the model name.

This change has the side-effect of bringing model name to metrics for a number of services that were accidentally omitting it before.

src/pipecat/services/openai/stt.py

@@ -221,6 +221,11 @@ class OpenAIRealtimeSTTService(WebsocketSTTService):
 
         super().__init__(
             ttfs_p99_latency=ttfs_p99_latency,
+            settings=OpenAIRealtimeSTTSettings(
+                model=model,
+                language=language,
+                prompt=prompt,
+            ),
             **kwargs,
         )
 
@@ -232,13 +237,6 @@ class OpenAIRealtimeSTTService(WebsocketSTTService):
         self._noise_reduction = noise_reduction
         self._should_interrupt = should_interrupt
 
-        self._settings = OpenAIRealtimeSTTSettings(
-            model=model,
-            language=language,
-            prompt=prompt,
-        )
-        self._sync_model_name_to_metrics()
-
         self._receive_task = None
         self._session_ready = False
         self._resampler = create_stream_resampler()