Do not enqueue unused css and js

Hi guys,

please delete these four lines:

https://plugins.trac.ww.wp.xz.cn/browser/wp-rest-filter/tags/1.4.3/public/class-wp-rest-filter-public.php#L140

https://plugins.trac.ww.wp.xz.cn/browser/wp-rest-filter/tags/1.4.3/public/class-wp-rest-filter-public.php#L163

https://plugins.trac.ww.wp.xz.cn/browser/wp-rest-filter/tags/1.4.3/admin/class-wp-rest-filter-admin.php#L140

https://plugins.trac.ww.wp.xz.cn/browser/wp-rest-filter/tags/1.4.3/admin/class-wp-rest-filter-admin.php#L163

Those lines include the not required public css and js files (the files do not have any content) and thus reduce the performance of each page using this plugin due to two more useless requests in admin + frontend.

Thanks and best regards,

Jan