GroundHeatExchangerHorizontalTrench: cloning to another model doesn't bring the Site:GroundTemperature:Undisturbed:XXX object

Issue overview

• Related to #4734

Current Behavior

Cloning doesn't bring the object to a new model.

Expected Behavior

Should clone it as it's required.

Steps to Reproduce

m = Model.new
hx = GroundHeatExchangerHorizontalTrench.new(m)
puts hx
m2 = Model.new
hx.clone(m2)
puts m2


OS:Version,
  {d12a3c48-451e-4dac-954c-494e8a18c4ed}, !- Handle
  3.7.0;                                  !- Version Identifier

OS:GroundHeatExchanger:HorizontalTrench,
  {e8e722ef-33cf-429b-968b-62e0cdd9ca15}, !- Handle
  Ground Heat Exchanger Horizontal Trench 1, !- Name
  ,                                       !- Inlet Node Name
  ,                                       !- Outlet Node Name
  0.004,                                  !- Design Flow Rate {m3/s}
  75,                                     !- Trench Length in Pipe Axial Direction {m}
  2,                                      !- Number of Trenches
  2,                                      !- Horizontal Spacing Between Pipes {m}
  0.016,                                  !- Pipe Inner Diameter {m}
  0.02667,                                !- Pipe Outer Diameter {m}
  1.25,                                   !- Burial Depth {m}
  1.08,                                   !- Soil Thermal Conductivity {W/m-K}
  962,                                    !- Soil Density {kg/m3}
  2576,                                   !- Soil Specific Heat {J/kg-K}
  0.3895,                                 !- Pipe Thermal Conductivity {W/m-K}
  641,                                    !- Pipe Density {kg/m3}
  2405,                                   !- Pipe Specific Heat {J/kg-K}
  30,                                     !- Soil Moisture Content Percent {percent}
  50,                                     !- Soil Moisture Content Percent at Saturation {percent}
  ,                                       !- Undisturbed Ground Temperature Model                          <---------- /!\ BLANK!
  0.408;                                  !- Evapotranspiration Ground Cover Parameter

Possible Solution

Adjust clone / parent-child relationship.

Details

Environment

Some additional details about your environment for this issue (if relevant):

• Platform (Operating system, version): all
• Version of OpenStudio (if using an intermediate build, include SHA): 3.7.0

Context

Reported at https://github.com/openstudiocoalition/OpenStudioApplication/issues/649 and https://unmethours.com/question/97673/horizontal-ground-heat-exchanger/