General: Ensure consistent type for integer properties of WP_Post, WP_Term, and WP_User.

Previously, these properties could be unexpectedly converted to strings in some contexts.

This applies to the following functions:

* `sanitize_post_field()`
* `sanitize_term_field()`
* `sanitize_user_field()`

and the following properties:

* `WP_Post::ID`
* `WP_Post::post_parent`
* `WP_Post::menu_order`
* `WP_Term::term_id`
* `WP_Term::term_taxonomy_id`
* `WP_Term::parent`
* `WP_Term::count`
* `WP_Term::term_group`
* `WP_User::ID`

Props grantmkin, SergeyBiryukov.
Fixes #53235. See #52995.

git-svn-id: https://develop.svn.wordpress.org/trunk@50935 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/user.php

@@ -1530,6 +1530,12 @@ function sanitize_user_field( $field, $value, $user_id, $context ) {
 	} elseif ( 'js' === $context ) {
 		$value = esc_js( $value );
 	}
+
+	// Restore the type for integer fields after esc_attr().
+	if ( in_array( $field, $int_fields, true ) ) {
+		$value = (int) $value;
+	}
+
 	return $value;
 }