The list of businesses cutting their ties to Russia grew longer on Wednesday, leaving Russians with access to yet fewer Western products and services as the world severs trade ties in anger at Russia’s invasion of Ukraine. One of the latest businesses to announce it had slammed the door shut was the maintenance subsidiary of Lufthansa, which is no longer servicing planes for Russian customers. The chief executive of Lufthansa Technik, Johannes Bußmann, made the announcement during the presentation of its annual numbers on Wednesday. The subsidiary has contracts with about a dozen Russian airli…