Privacy: Add `$request` to `$email_data` to make it available to all filters.

Props desrosj.
Fixes #44379.

git-svn-id: https://develop.svn.wordpress.org/trunk@43477 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/user.php

@@ -3368,6 +3368,7 @@ function wp_send_user_request( $request_id ) {
 	}
 
 	$email_data = array(
+		'request'     => $request,
 		'email'       => $request->email,
 		'description' => wp_user_request_action_description( $request->action_name ),
 		'confirm_url' => add_query_arg( array(