[commands] Fix delete_after not working with interaction Context.send

discord/ext/commands/context.py

@@ -727,7 +727,11 @@ class Context(discord.abc.Messageable, Generic[BotT]):
         }
 
         if self.interaction.response.is_done():
-            return await self.interaction.followup.send(**kwargs, wait=True)
+            msg = await self.interaction.followup.send(**kwargs, wait=True)
+        else:
+            await self.interaction.response.send_message(**kwargs)
+            msg = await self.interaction.original_message()
 
-        await self.interaction.response.send_message(**kwargs)
-        return await self.interaction.original_message()
+        if delete_after is not None:
+            await msg.delete(delay=delete_after)
+        return msg