refactor: Improve code readability and structure across TTS modules

app/api/v1/tts.py

@@ -206,8 +206,6 @@ async def delete_tts(
 
         await tts_service.delete_tts(tts_id=tts_id, user_id=current_user.id)
 
-        return {"message": "TTS generation deleted successfully"}
-
     except ValueError as e:
         raise HTTPException(
             status_code=status.HTTP_404_NOT_FOUND,
@@ -223,3 +221,5 @@ async def delete_tts(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail=f"Failed to delete TTS: {e!s}",
         ) from e
+    else:
+        return {"message": "TTS generation deleted successfully"}