How to Hide Gravity Booster ( Style & Layouts ) Admin Menus

function plt_hide_styles_and_layouts_for_gravity_forms_menus() {
	//Hide "Styles & Layouts for GF".
	remove_menu_page('stla_licenses');
	//Hide "Styles & Layouts for GF → Licenses".
	remove_submenu_page('stla_licenses', 'stla_licenses');
	//Hide "Styles & Layouts for GF → Documentation".
	remove_submenu_page('stla_licenses', 'stla-documentation');
	//Hide "Styles & Layouts for GF → Add-Ons".
	remove_submenu_page('stla_licenses', 'stla-addons');
}

add_action('admin_menu', 'plt_hide_styles_and_layouts_for_gravity_forms_menus', 11);

Where do I put this code?