PHP 8.1 deprecation notice for generate_set_comment_form_defaults

Hi there,

this code in generate_set_comment_form_defaults:

	$defaults['comment_notes_before'] = null;
	$defaults['comment_notes_after']  = null;

leads to a deprecation notice:

2023/01/29 12:26:34 [error] 2015302#2015302: *11780826 FastCGI sent in stderr: "PHP message: PHP Deprecated: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in /wp-includes/comment-template.php on line 2512" while reading response header from upstream,

I fixed it locally by replacing null with an empty string "". It would be great if you could upstream that.
Thanks!