Skip dummy fallback TTS, remove mimic as default fallback. (#51)

* remove mimic as default fallback, skip fallback init if empty or same as main TTS

* added another check for empty fallback_tts

ovos_audio/service.py

@@ -315,8 +315,9 @@ def _maybe_reload_tts(self):
                 self._tts_hash = config.get("module", "")
 
         # if fallback TTS is the same as main TTS dont load it
-        if config.get("module", "") == config.get("fallback_module", ""):
-            return
+        if config.get("module", "") == config.get("fallback_module", "") or not config.get("fallback_module", ""):
+            LOG.debug("Skipping fallback TTS init, fallback is empty or same as main TTS")
+            return            
 
         if not config.get('preload_fallback', True):
             LOG.debug("Skipping fallback TTS init")
@@ -354,7 +355,9 @@ def _get_tts_fallback(self):
         """Lazily initializes the fallback TTS if needed."""
         if not self.fallback_tts:
             config = Configuration()
-            engine = config.get('tts', {}).get("fallback_module", "mimic")
+            engine = config.get('tts', {}).get("fallback_module", "")
+            if not engine:
+                return
             cfg = {"tts": {"module": engine,
                            engine: config.get('tts', {}).get(engine, {})}}
             self.fallback_tts = TTSFactory.create(cfg)