Revert "Ability to reload application command callbacks (#647)"

This reverts commit 51d110b.

Author: Lulalaby

discord/bot.py

@@ -124,14 +124,7 @@ def add_application_command(self, command: ApplicationCommand) -> None:
 
         if self.debug_guilds and command.guild_ids is None:
             command.guild_ids = self.debug_guilds
-
-        for cmd in self.pending_application_commands:
-            if cmd == command:
-                command.id = cmd.id
-                self._application_commands[command.id] = command
-                break
-        else:
-            self._pending_application_commands.append(command)
+        self._pending_application_commands.append(command)
 
     def remove_application_command(
         self, command: ApplicationCommand
@@ -490,32 +483,25 @@ async def process_application_commands(self, interaction: Interaction) -> None:
         try:
             command = self._application_commands[interaction.data["id"]]
         except KeyError:
-            for cmd in self.application_commands:
-                if (
-                    cmd.name == interaction.data["name"]
-                    and interaction.data["guild_id"] in cmd.guild_ids
-                ):
-                    command = cmd
-                    break
-            else:
-                return self.dispatch("unknown_command", interaction)
-        if interaction.type is InteractionType.auto_complete:
-            ctx = await self.get_autocomplete_context(interaction)
+            self.dispatch("unknown_command", interaction)
+        else:
+            if interaction.type is InteractionType.auto_complete:
+                ctx = await self.get_autocomplete_context(interaction)
+                ctx.command = command
+                return await command.invoke_autocomplete_callback(ctx)
+            
+            ctx = await self.get_application_context(interaction)
             ctx.command = command
-            return await command.invoke_autocomplete_callback(ctx)
-        
-        ctx = await self.get_application_context(interaction)
-        ctx.command = command
-        self.dispatch("application_command", ctx)
-        try:
-            if await self.can_run(ctx, call_once=True):
-                await ctx.command.invoke(ctx)
+            self.dispatch("application_command", ctx)
+            try:
+                if await self.can_run(ctx, call_once=True):
+                    await ctx.command.invoke(ctx)
+                else:
+                    raise CheckFailure("The global check once functions failed.")
+            except DiscordException as exc:
+                await ctx.command.dispatch_error(ctx, exc)
             else:
-                raise CheckFailure("The global check once functions failed.")
-        except DiscordException as exc:
-            await ctx.command.dispatch_error(ctx, exc)
-        else:
-            self.dispatch("application_command_completion", ctx)
+                self.dispatch("application_command_completion", ctx)
 
     def slash_command(self, **kwargs):
         """A shortcut decorator that invokes :func:`.ApplicationCommandMixin.command` and adds it to