Encrypted chat app Signal is adding payments to the services it provides, a long-expected move and one the company is taking its time on. A U.K.-only beta program will allow users to trade the cryptocurrency MobileCoin quickly, easily, and most importantly, privately. If you’re in the U.K., or have some way to appear to be, you’ll notice a new Signal Payments feature in the app when you update. All you need to do to use it is link a MobileCoin wallet after you buy some on the cryptocurrency exchange FTX,…