Fix AMAC HV switch overwrite
This prevents the OPC server from opening the AMAC HV switches by default. Of course, it now means that the server will close the switches by default, but this is preferred behavior. Previously, the server was opening the switches while HV was on, which caused a buildup of charge on the capacitor.
We should immediately merge this as a hotfix, but we probably want to come up with a more permanent solution. We should think about a single way to set the HV switches, and stick to that (right now, this method is not even used).