Fix AttributeError in log_uncached_deleted_message when channel is None

Author: oliveman-au

bot/exts/moderation/modlog.py

@@ -589,6 +589,9 @@ async def log_uncached_deleted_message(self, event: discord.RawMessageDeleteEven
             return
 
         channel = self.bot.get_channel(event.channel_id)
+        if channel is None:
+            log.trace(f"Channel {event.channel_id} not found, skipping uncached message delete log.")
+            return
 
         if channel.category:
             response = (