3D magnet: update labview driver and LvDCOM for new setup

## Where?

3D magnet driver (which is an LvDCOM over a manufacturer VI)

## How?

Due to the failure of a temperature controller, the kit is being physically rewired to (re-)use one of the existing lakeshores for temperature monitoring and controls of some channels.

Exact details of setup changes from cryogenics group to follow.

Rob D has hacked the labview driver on LARMOR to match the state of the hardware physically. However we should implement these changes properly (in source control etc) and also update the LvDCOM as appropriate. See `LabVIEW Modules\Drivers\Scientific Instruments` on larmor.

This will be required before the next time the 3d magnet is used on any instrument - cryogenics are asking for this to be done by end of August.

## Acceptance criteria
- [ ] SCIMAG3D labview driver & lvdcom wrapper are adjusted to match the new setup of the underlying hardware.
- [ ] Changes are tested

## How to Test
_verbose instructions for reviewer to test changes
(**Add before making a PR**)_