Registers a provided user Id to the screen reader framework and allows the screen reader user to receive and respond to accessible events and accessible input. Does nothing if the passed in Id is already registered. Note: A successfully registered screen reader user is deactivated by default and will not respond to accessible events or accessible input. You need to call ActivateUser() to allow the newly registered screen reader user to respond to the accessible events and accessible input. FScreenReaderReply::Handled() if the screen reader user is successfully registered. Else FScreenReaderReply::Unhandled() is returned.