Decryption key:
* Improved the Remove Group By option
- if WP_Query selects columns from only wp_posts and does not join to other tables, we remove DISTINCT and GROUP BY for extra speed
- if WP_Query joins to other tables, but still only selects columns from wp_posts, we swap GROUP BY for DISTINCT to remove the extra sort operation
- improved it so it's no longer called experimental, it should be safe in all cases so long as no plugins rely on items coming back in ID order for some reason
- also improved it so that it catches more cases
* Added new SPRO_ALLOW_NAV_MENU_ITEMS_FILTERS definition
- this is since I found that nav_menu_items tends to have suppress_filters applied