Deprecation notice from InputSlider control

[DeoThemes]

Issue description:

I'm using an example from your docs and got this notice:

Deprecated: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in C:\Users\...\Local Sites\envision-blocks\app\public\wp-content\themes\envisionx\includes\customizer\kirki\pro-src\packages\kirki-pro-input-slider\src\Control\InputSlider.php on line 74

Version used:

5

Using theme_mods or options?

theme_mods

Code to reproduce the issue (config + field(s))

new \Kirki\Pro\Field\InputSlider(
	[
		'settings'    => 'kirki_pro_slider',
		'label'       => esc_html__( 'Responsive Slider Control', 'kirki' ),
		'section'     => 'section_id',
		'transport'   => 'postMessage',
		'default'     => '50px',
		'choices'     => [
			'min'  => 0,
			'max'  => 100,
			'step' => 1,
		],
	]
);