Throw error if hyperion started in plate screening mode

[DominicOram]

i03 can be run in plate screening mode occasionally. However, this mode is not supported by hyperion and so if hyperion is triggered whilst in it then it does nothing. There should be a PV that we can use to check this, we should look in GDA or ask Neil what this PV is.

Acceptance Criteria

• Hyperion checks the PV that tells us if we're in plate screening mode
• If we are hyperion raises an error suggesting we turn hyperion off
• Confirm that GDA shouldn't be calling hyperion when in this mode in the first place