Privacy: add `wp_page_for_privacy_policy` to `populate_options()`.

Props ocean90.
Fixes #44076.

git-svn-id: https://develop.svn.wordpress.org/trunk@43267 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/schema.php

@@ -532,6 +532,9 @@ function populate_options() {
 		// 4.4.0
 		'medium_large_size_w'             => 768,
 		'medium_large_size_h'             => 0,
+
+		// 4.9.6
+		'wp_page_for_privacy_policy'      => 0,
 	);
 
 	// 3.3