LKSH336: use getAOUT to read channels 3&4 in place of getHTR

[Tom-Willemsen]

On testing with cryogenics and scientists, the functionality added to read channels 3 & 4 on a lakeshore works except that the readback comes back as 0. On further investigation a slightly different command is needed to read channels 3&4. the command is already present in protocol file as getAOUT, just need to call it instead of getHTR.

Note: this is already patched on LARMOR and ZOOM

Needed for running 3D magnet

[boeuf-codes]

Pull requests:

• Ticket 7343 EPICS-ioc#727
• Ticket 7343 EPICS-lakeshore#6
• Ticket #7343: Release notes #7364