You can intercept this email before it is sent using the phpmailer_init
hook.
By default, this hook fires before any email is sent. In the function below, $phpmailer
will be an instance of PHPMailer, and you can use its methods to remove the default recipient and manipulate the email before it is sent.
add_action('phpmailer_init', 'wse199274_intercept_registration_email');
function wse199274_intercept_registration_email($phpmailer){
$admin_email = get_option( 'admin_email' );
# Intercept username and password email by checking subject line
if( strpos($phpmailer->Subject, 'Your username and password info') ){
# clear the recipient list
$phpmailer->ClearAllRecipients();
# optionally, send the email to the WordPress admin email
$phpmailer->AddAddress($admin_email);
}else{
#not intercepted
}
}