A recent change breaks custom help Commands

The recent change at https://github.com/urfave/cli/blob/fd14621cbcd644aa35483480d40f7cdf7b69f4c0/command_run.go#L144C29-L144C53 assumes any command named "help" must be the default Help handler. This breaks applications with custom Help commands.

There are lots of reasons to want a custom Help command. e.g. to write to the cmd.Root()'s OutWriter or ErrWriter instead of to stdout.
