fix: don't upload attachments in dms (#3412)

* fix: don't upload attachments in dms

closes GH-3403

Author: onerandomusername

bot/exts/utils/attachment_pastebin_uploader.py

@@ -77,8 +77,8 @@ async def on_message_delete(self, message: discord.Message) -> None:
     @commands.Cog.listener()
     async def on_message(self, message: discord.Message) -> None:
         """Listens for messages containing attachments and offers to upload them to the pastebin."""
-        # Check if the message contains an embedded file and is not sent by a bot.
-        if message.author.bot or not any("charset" in a.content_type for a in message.attachments):
+        # Check if the message contains an embedded file and is not sent by a bot or in DMs.
+        if message.author.bot or not message.guild or not any("charset" in a.content_type for a in message.attachments):
             return
 
         log.trace(f"Offering to upload attachments for {message.author} in {message.channel}, message {message.id}")