Privacy: Introduce a function to count user requests by type

[birgire]

The user request list tables use WP_Privacy_Requests_Table::get_request_counts( $type ) to count user requests by type.

If export- and erase bubble counts will be added in #44000 and if e.g. plugins or core will add request stats to the dashboard ( e.g. "At a glance" or "Activity" metaboxes), then it makes sense to introduce a function like:

wp_count_user_requests( $type )

where type is either 'remove_personal_data' and 'export_personal_data'.

An alternative would be if wp_count_post( $post_type = 'user_request' ) would support $post_name as well, for the request types.

[birgire]

44034.diff​ is a an example that takes WP_Privacy_Requests_Table::get_request_counts( $type ) into a reusable wp_count_user_requests( $type ) function that's filterable with the wp_count_user_requests filter.

[desrosj]

Moving to the new Privacy component.