Fix: failing commits while applying changes on the network element

If read-only fields are sent to the network element with a SetRequest an
error is thrown by the network element. This can be prevented by
filtering all the read-only fields with the help of
`ygot.PruneConfigFalse` - since they are not needed in a SetRequest.

plugins/sdk/deviceModel.go

@@ -176,6 +176,10 @@ func (d *DeviceModel) Diff(original, modified []byte) (*gpb.Notification, error)
 		return nil, err
 	}
 
+	//TODO: This should be changed to be optional
+	ygot.PruneConfigFalse(d.schema.RootSchema(), originalAsValidatedCopy)
+	ygot.PruneConfigFalse(d.schema.RootSchema(), modifiedAsValidatedCopy)
+
 	return ygot.Diff(originalAsValidatedCopy, modifiedAsValidatedCopy)
 }