welcome_user_msg_filter( string $text )

function welcome_user_msg_filter( $text ) {
	if ( !$text ) {
		remove_filter( 'site_option_welcome_user_email', 'welcome_user_msg_filter' );

		/* translators: Do not translate USERNAME, PASSWORD, LOGINLINK, SITE_NAME: those are placeholders. */
		$text = __( 'Hello USERNAME,

Your new account is set up.

You can log in with the following information:
Username: USERNAME
Password: PASSWORD
LOGINLINK

Thanks!

--The Team @ SITE_NAME' );
		update_site_option( 'welcome_user_email', $text );
	}
	return $text;
}