Triggers when a user updates their profile through the [rcp_profile_editor] shortcode.
Parameters:
- $user_id - ID of the user editing their profile.
- $userdata (array) - Array of WP_User fields that were submitted through the form ('ID', 'first_name', 'last_name', 'display_name', 'user_email').
- $old_data (WP_User) - Old user WP_User object, before the update.