Google Messages users might soon have a bit less control over how they text individual contacts. Code spotted in the latest open beta build of the app suggests that Google is laying the groundwork to remove the toggle that lets you disable Rich Communication Services (RCS) on a chat-by-chat basis. Right now, if a specific conversation gets glitchy or starts filling up with promotional spam, you can simply open that contact’s info screen and flip a switch labeled “Only send SMS and MMS messages.” That forces Google Messages to fall back to classic texting just for that person while keeping…