Custom Color Palette in WordPress Color Picker

I found this article on Custom Color Palette in WordPress Color Picker (it’s the one used for theme customisation etc. I want the custom palette colors on).

I tried putting the following in a child theme (based on SiteOrigin Vantage) and it changed nothing. Does this have to be implemented in the main theme? Or am I missing something else?

childtheme/functions.php code:

function custom_scripts() {
	wp_enqueue_script('custom_scripts', get_template_directory_uri() . '/js/custom.js');
}
add_action('admin_enqueue_scripts', 'custom_scripts');

childtheme/js/custom.js code:

jQuery(function($) {
	if (typeof $.wp !== 'undefined' && typeof $.wp.wpColorPicker !== 'undefined') {
		$.wp.wpColorPicker.prototype.options = {
			// add your custom colors here
			palettes: [
				'#556270',
				'#4ecdc4',
				'#c7f464',
				'#ff6b6b',
				'#c44d58',
				'#ecca2e',
				'#bada55'
			]
		};
	}
});

Any help would be greatly appreciated.