The Dimensions field does not keep the default choices

[irisinteractive]

Issue description:

When adding a Dimensions type field with default values ​​and output as root css variables, the default values ​​are overwritten with a null value.

Version used:

5.0.0

Using theme_mods or options?

options

PHP error messages that might be related

Nothing

JS error messages that might be related

Nothing

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

new \Kirki\Field\Dimensions( array(
  "description" => "",
  "priority" => 9999,
  "default" => array(
    "Vertical" => "20px",
    "Horizontal" => "20px"
  ),
  "capability" => "iris_manage_customizer",
  "option_type" => "option",
  "kirki_config" => "iris_customize_config",
  "label" => "Marges internes",
  "section" => "iris-section-main-button",
  "output" => array(
    array(
      "element" => ":root",
      "property" => "--iris--button--padding-y",
      "choice" => "Vertical",
      "context" => array(
        "editor",
        "front"
      ),
    ),
    array(
      "element" => ":root",
      "property" => "--iris--button--padding-x",
      "choice" => "Horizontal",
      "context" => array(
        "editor",
        "front"
      )
    )
  ),
  "settings" => "iris_customize_option_button_padding",
  "required" => array()
) );

In the init method of the kirki/kirki-packages/field-dimensions/src/Dimensions.php file, I tested two fixes from line 80:

		new \Kirki\Field\Generic(
			wp_parse_args(
				array(
+					'settings'    => $args['settings'] . '-kirki-generic',
					'type'              => 'kirki-generic',
					'default'           => '',
					'wrapper_opts'      => array(
						'gap' => 'small',
					),
					'sanitize_callback' => isset( $args['sanitize_callback'] ) ? $args['sanitize_callback'] : array( __CLASS__, 'sanitize' ),
					'choices'           => array(
						'type'        => 'hidden',
						'parent_type' => 'kirki-dimensions',
					),
				),
				$args
			)
		);

OR

		new \Kirki\Field\Generic(
			wp_parse_args(
				array(
					'type'              => 'kirki-generic',
+					'default'           => isset( $args['default'] ) ? $args['default'] : '',
					'wrapper_opts'      => array(
						'gap' => 'small',
					),
					'sanitize_callback' => isset( $args['sanitize_callback'] ) ? $args['sanitize_callback'] : array( __CLASS__, 'sanitize' ),
					'choices'           => array(
						'type'        => 'hidden',
						'parent_type' => 'kirki-dimensions',
					),
				),
				$args
			)
		);

Looking forward to a resolution, thank you!