fix: throw if id null

review comment

Connectors/Rhino/Speckle.Connectors.GrasshopperShared/Components/Collections/CreateCollection.cs

@@ -199,7 +199,7 @@ public class CreateCollection : VariableParameterComponentBase
             if (instanceGoo.CastFrom(obj))
             {
               instanceGoo.Value.Path = childPath;
-              wrapperGoo.Value.Parent = parentCollection;
+              instanceGoo.Value.Parent = parentCollection;
               parentCollection.Elements.Add(instanceGoo.Value);
             }
             else

Connectors/Rhino/Speckle.Connectors.GrasshopperShared/Parameters/Wrappers/SpeckleBlockInstanceWrapper.cs

@@ -59,10 +59,14 @@ public class SpeckleBlockInstanceWrapper : SpeckleObjectWrapper
     set
     {
       _definition = value;
+
       if (_definition != null)
       {
-        _definition.ApplicationId ??= Guid.NewGuid().ToString();
-        _instanceProxy.definitionId = _definition.ApplicationId;
+        _instanceProxy.definitionId =
+          _definition.ApplicationId
+          ?? throw new InvalidOperationException(
+            "Block definition must have ApplicationId before being assigned to instance"
+          );
       }
     }
   }