Deployment of App fails when modelKey of included model has been updated and the model has a message start event subscription

**Describe the bug**
We have a process model which is initiated via a message start event. Just found out that the deployment of the App containing this model fails when the model key was updated, with a somewhat hard to understand error message
```there already is a message event subscription for the message with name 'startMyFantasticProcess' ```

**Expected behavior**
The deployment to succeed

**Code**
If applicable, add the code that you are using when having the issue.

**Additional context**
This is on Flowable 6.7.2.

The reason for this error is that when deploying the method BpmnDeploymentHelper.updateTimersAndEvents calls
```eventSubscriptionManager.removeObsoleteMessageEventSubscriptions(previousProcessDefinition);```
which will not find the EventSubscriptionEntity to delete before the deployment since the name was changed.

So the fix would probably be to update the modelKey reference in that table whenever a modelKey is updated.

Beginnen Sie in BpmnDeploymentHelper.updateTimersAndEvents und verfolgen Sie eventSubscriptionManager.removeObsoleteMessageEventSubscriptions(previousProcessDefinition). Untersuchen Sie, wie Message-Event-Subscriptions den modelKey beibehalten, wenn ein eingebundenes Modell umbenannt wird. Erledigt ist es, wenn das Deployment der App nach der Änderung des modelKey erfolgreich ist und die bestehende Message-Start-Event-Subscription nicht länger einen Fehler wegen eines doppelten Namens verursacht.

Vom Indexierungsmodell aus dem Issue-Text verfasst.