GUI: Run control refused to set limits with no warning

As an instrument scientist I want to be able to override run control but when I used the control to do this it refused my change. There was no error. This ticket is to display an error if the run control setting can not be set. This is caused by failing an `uncheckedWrite` in `RunControlSetter` (see #4929). Fix is to change this to a `write` and catch the exception and display it as an error to the user.