Add new function called `wp_get_lastest_revision_id_and_total_count`, that performs an optimized query to get the last revision and total and use it in `WP_REST_Posts_Controller` class.
Props Spacedmonkey, timothyblynjacobs, furi3r, peterwilsoncc.
Fixes#55857.
git-svn-id: https://develop.svn.wordpress.org/trunk@53759 602fd350-edb4-49c9-b593-d223f7449a82