apsara_datacenter_device_allocation bug in Read() after manually clearing interface map via GUI

[chrismarget-j]

The Read() function calls state.GetInterfaceMapName() even after determining that no interface map is currently assigned to the node.

state.GetInterfaceMapName() examines a long-ish graph traversal:

(system)->(logical_device)<-(interface_map)->(device_profile)

When that search comes up empty (of course it does, the interface_map is null) we get an error like:

│ Error: interface map <null> not compatible with node "spine1" (etoQcsplnr5iwTNsPWM)
│ 
│   with apstra_datacenter_device_allocation.spine1,
│   on main.tf line 21, in resource "apstra_datacenter_device_allocation" "spine1":
│   21: resource "apstra_datacenter_device_allocation" "spine1" {
│ 
│ expected 1 path linking system "spine1", logical device (any), interface map "" and device profile "", got 0
│ query:
│ "node(type='system',id='etoQcsplnr5iwTNsPWM').out(type='logical_device').node(type='logical_device').in_(type='logical_device').node(type='interface_map',name='n_interface_map',id='').out(type='device_profile').node(type='device_profile',id='')"

The lookup should not have been attempted.