Patch default help for user provided _CliInternalArgParser

[grabear]

In my project we use _CliInternalArgParser directly with add_help=True, which causes an argparse error:

argparse.ArgumentError: argument -h/--help: conflicting option strings: -h, --help

This patch checks the registered actions for the argparse._HelpAction type, to prevent the issue.

To reproduce this error:

from pydantic_settings.sources.providers.cli import _CliInternalArgParser
from pydantic_settings import CliSettingsSource
from pydantic import BaseModel

CliSettingsSource(root_parser=_CliInternalArgParser(add_help=True), settings_cls=type("Model", (BaseModel,), {}))

Selected Reviewer: @samuelcolvin

[hramezani]

Thanks @grabear for the PR. Please fix the lint error and add a test.

@kschwab Could you please review it?

[grabear]

@hramezani @kschwab fixed it!

[hramezani]

@hramezani @kschwab fixed it!

please add test

[hramezani]

Closing due to inactivity