REST API: Synchronize permission checks in `::get_items_permissions_check()`...

REST API: Synchronize permission checks in `::get_items_permissions_check()` methods for post types, post statuses, and users:

* Only query post types with `'show_in_rest' => true` instead of looping over all post types and checking the `show_in_rest` property separately.
* Return from the `foreach()` loop as soon as the permission check succeeded.

Props pbiron, TimothyBlynJacobs, SergeyBiryukov.
Fixes #49118.
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git-svn-id: https://core.svn.wordpress.org/trunk@46834 1a063a9b-81f0-0310-95a4-ce76da25c4cd