Process doesn't support modelerTemplate

[philippfromme]

Due to

{
      "name": "TemplateSupported",
      "isAbstract": true,
      "extends": [
        "bpmn:FlowElement"
      ],
      "properties": [
        {
          "name": "modelerTemplate",
          "isAttr": true,
          "type": "String"
        }
      ]
    }

processes do not support modelerTemplate which is therefore not applied correctly.