fix: Implement owner check for eval command using a dedicated function

cogs/eval_cog.py

@@ -114,8 +114,12 @@ class EvalCog(commands.Cog):
             else:
                 await ctx.send(f'```py\n{value}{ret}\n```')
 
+    async def is_owner_check(interaction: discord.Interaction) -> bool:
+        """Checks if the interacting user is the bot owner."""
+        return interaction.user.id == interaction.client.owner_id
+
     @app_commands.command(name="eval", description="Evaluate Python code using a modal form.")
-    @app_commands.is_owner()
+    @app_commands.check(is_owner_check)
     async def eval_slash(self, interaction: discord.Interaction):
         """Opens a modal to evaluate Python code."""
         await interaction.response.send_modal(EvalModal())