default to empty text

cogs/bridge.py

@@ -1818,7 +1818,7 @@ async def stickers_to_urls(stickers):
         if source == 'discord' and not system:
             if len(message.stickers) > 0:
                 stickertext = '\n'.join(await stickers_to_urls(message.stickers))
-        if (len(message.content) > 0 or len(content_override) > 0) and len(stickertext) > 0:
+        if (len(message.content) > 0 or len(content_override if not content_override is None else '') > 0) and len(stickertext) > 0:
             stickertext = '\n' + stickertext
 
         # Broadcast message