Silence krisp_audio import logs on auto-import

The two logger.error lines in krisp_instance.py fired at module-load time
whenever anything transitively imported it (e.g. pipecat.turns.user_start
pulling in krisp_viva_ip_user_turn_start_strategy), producing noisy output
for users who never asked for Krisp. Drop the log calls and raise a more
informative ImportError that names the affected classes so direct
importers still get clear guidance.

src/pipecat/audio/krisp_instance.py

@@ -15,9 +15,11 @@ from loguru import logger
 try:
     import krisp_audio
 except ModuleNotFoundError as e:
-    logger.error(f"Exception: {e}")
-    logger.error("In order to use the Krisp instance, you need to install krisp_audio.")
-    raise ImportError(f"Missing module: {e}") from e
+    raise ImportError(
+        "krisp_audio is required for Krisp audio features. "
+        "Install it to use KrispVivaFilter, KrispVivaVadAnalyzer, "
+        "KrispVivaTurn, or KrispVivaIPUserTurnStartStrategy."
+    ) from e
 
 
 # Mapping of sample rates (Hz) to Krisp SDK SamplingRate enums