Add more 55-series examples

Also:
- remove unnecessary pass-through `_update_settings` implementation in `FalSTTService`
- warn that `AsyncAITTSService` doesn't currently support runtime settings updates
- update how `GradiumTTSService._update_settings` checks for voice changes
- remove a couple of unnecessary args (because they specified defaults) in other examples

examples/foundational/14s-function-calling-sambanova.py

@@ -70,10 +70,7 @@ async def run_bot(transport: BaseTransport, runner_args: RunnerArguments):
         voice_id="71a7ad14-091c-4e8e-a314-022ece01c121",  # British Reading Lady
     )
 
-    llm = SambaNovaLLMService(
-        api_key=os.getenv("SAMBANOVA_API_KEY"),
-        model="Llama-4-Maverick-17B-128E-Instruct",
-    )
+    llm = SambaNovaLLMService(api_key=os.getenv("SAMBANOVA_API_KEY"))
     # You can also register a function_name of None to get all functions
     # sent to the same callback with an additional function_name parameter.
     llm.register_function("get_current_weather", fetch_weather_from_api)