HelpCommand checks gets overwritten when set to bot.help_command

[InterStella0]

Summary

When you use HelpCommand.add_check, and set to bot.help_command, it overwritten

Reproduction Steps

1. initialize the help command without checks kwarg
2. use HelpCommand.add_check, i.e in init or outside
3. assign to bot.help_command

Minimal Reproducible Code

help_command = commands.DefaultHelpCommand()
help_command.add_check(lambda ctx: False)
print(help_command._command_impl.checks) # [<function <lambda> at 0x000001E67FEE50D0>]
bot.help_command = help_command
print(help_command._command_impl.checks) # []
help_command.add_check(lambda ctx: False)
print(help_command._command_impl.checks) # [<function <lambda> at 0x000001E67FEE50D0>]

Expected Results

checks should be carried over after bot.help_command is set and not get overwritten.

Actual Results

checks are overwritten when setting to bot.help_command. This results in the checks not being applied when invoking the help command.

Intents

discord.Intents.all()

System Information

• Python v3.9.13-final
• discord.py v2.4.0-alpha
  • discord.py metadata: v2.4.0a5025+g041abf8b
• aiohttp v3.9.5
• system info: Windows 10 10.0.22631

Checklist

• [X] I have searched the open issues for duplicates.
• [X] I have shown the entire traceback, if possible.
• [X] I have removed my token from display, if visible.

Additional Context

checks do carried over if you set the checks kwarg on command_attrs.

help_command = commands.DefaultHelpCommand(command_attrs={'checks': [lambda ctx: False]})
help_command.add_check(lambda ctx: False)
bot.help_command = help_command
print(help_command._command_impl.checks)  # [<function <lambda> at 0x0000027E06E35160>, <function <lambda> at 0x0000027E06F089D0>]

Happens since HelpCommand._add_to_bot only copies command_attrs but left out checks on the actual command impl here. Since command impl there gets overwritten, the checks disappear.

A simple fix would just be command.checks = self._command_impl.checks after this line but I don't like my approach