Error of boundary event is lost when converting to xml at DeploymentBuilderImpl.class

**Describe the bug**
I try to deploy a bpmn model that has an error for an error boundary event but when I try to get file back the model doesn’t have the error anymore.
I tried with this file also: https://github.com/flowable/flowable-engine/blob/3cc4d5e225c7ab2ccbba5f95b9441c842f743307/modules/flowable-app-rest/src/main/resources/reviewSalesLead.bpmn20.xml#L11
I deploy my file like this:

`Deployment deployment = repositoryService.createDeployment()
.addBpmnModel(resourceName, model)
.deploy();`

and I am retrieving it like this:

`repositoryService.getProcessModel(processDefinitionId)`

I’ve noticed that inside DeploymentBuilderImpl.class here:

`public DeploymentBuilder addBpmnModel(String resourceName, BpmnModel bpmnModel) {
BpmnXMLConverter bpmnXMLConverter = new BpmnXMLConverter();
String bpmn20Xml = new String(bpmnXMLConverter.convertToXML(bpmnModel), StandardCharsets.UTF_8);
addString(resourceName, bpmn20Xml);
return this;
}`

My error is present at bpmn model but it’s not present at bpmn20Xml string.

**Expected behavior**
Error should be present when retrieving bpmn model

**Code**
`Deployment deployment = repositoryService.createDeployment()
.addBpmnModel(resourceName, model)
.deploy();`

**Additional context**
Flowable version: 7.1.0
used within Spring Boot app

Reproduce the round trip using DeploymentBuilderImpl.addBpmnModel with the reviewSalesLead.bpmn20.xml example, then inspect BpmnXMLConverter.convertToXML and the resulting bpmn20Xml string. Compare the error boundary event in the original BpmnModel, serialized XML, and repositoryService.getProcessModel result; done means the error remains present after deployment and retrieval.

Scritto dal modello di indicizzazione a partire dal testo della issue.