REST API: Add missing assertions to the view and embed context response data for the Users Controller.

Adds tests for responses where `context != 'edit'` the following properties are not included in the response data:
- `email`
- `locale`
- `registered_date`

Props thepelkus, jnylen0.
Fixes #39399.

Built from https://develop.svn.wordpress.org/trunk@39660


git-svn-id: http://core.svn.wordpress.org/trunk@39600 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-39659';
+$wp_version = '4.8-alpha-39660';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.