Critical CSS doesn't respect dependency order

[johnbillion]

When more than one critical CSS file is registered (for example, one from a parent theme and one from a child theme) the dependencies are not respected. They get output in the order in which add_asset() is called, not according to their dependencies.

In the code below, critical-first should be output first because it's a dependency of critical-second, but critical-second gets output first because that's the order in which add_asset() is called.

$styles = [
    [
        'condition'   => 'global',
        'deps'        => [
            'critical-first',
        ],
        'handle'      => 'critical-second',
        'load_hook'   => 'am_critical',
        'load_method' => 'inline',
        'src'         => MY_PATH . '/critical-second.css',
        'version'     => 1,
    ],
    [
        'condition'   => 'global',
        'deps'        => [],
        'handle'      => 'critical-first',
        'load_hook'   => 'am_critical',
        'load_method' => 'inline',
        'src'         => MY_PATH . '/critical-first.css',
        'version'     => 1,
    ],

];

array_map( [ \Asset_Manager_Styles::instance(), 'add_asset' ], $styles );