fix some error messages being sent twice

cogs/emote.py

@@ -94,15 +94,6 @@ class Emotes(commands.Cog):
 
 		return True
 
-	@commands.Cog.listener()
-	async def on_command_error(self, context, error):
-		if isinstance(error, (errors.EmoteManagerError, errors.MissingManageEmojisPermission)):
-			await context.send(str(error))
-
-		if isinstance(error, commands.NoPrivateMessage):
-			await context.send(
-				f'{utils.SUCCESS_EMOJIS[False]} Sorry, this command may only be used in a server.')
-
 	@commands.command(usage='[name] <image URL or custom emote>')
 	async def add(self, context, *args):
 		"""Add a new emote to this server.