Update error-messages.md

I am from Microsoft Azure CXP Chat Team. Got a customer case recently for the respective error message that cx got while trying to delete a VM on Azure and we found that this error is not documented in any MS public Docs. While I found out few such issues reported in Microsoft Community Threads.
hence updating this document with the same.

Customer Error : Failed to update associated resources for virtual machine 'xxx'
Message : An error occurred while updating associated resources for virtual machine 'xxx'. To delete the virtual machine without updating associated resources first, try again without updating any associated resource deletion states. 
Error: 'Changing property 'creationData' is not allowed.'

Author: Ekta-Microsoft

support/azure/virtual-machines/windows/error-messages.md

@@ -210,5 +210,6 @@ This section lists the common error messages you might encounter when managing V
 |  VMRedeploymentFailed  |  VM '{0}' redeployment failed due to an internal error. Please retry later.  |
 |  VMRedeploymentTimedOut  |  Redeployment of VM '{0}' didn't finish in the allotted time. It might finish successfully in sometime. Else, you can retry the request.  |
 |  VMStartTimedOut  |  VM '{0}' did not start in the allotted time. The VM may still start successfully. Please check the power state later.  |
+|  Changing property 'creationData' is not allowed  |  Failed to update associated resources for VM '{0}'. An error occurred while updating associated resources for VM '{0}'. To delete the virtual machine without updating associated resources first, try again without updating any associated resource deletion states.   |
 
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