PUT Annotation with added via field results in erronous HTTP 409

[GGoetzelmann]

Describe the bug

The user is unable to perform an update on an annotation that adds a via property.

To Reproduce
Steps to reproduce the behavior:

1. create anntation without using the via property
2. PUT via to annotation
3. get Error

   "status":"409",
   "error":"UnallowedPropertyChangeException",
   "message":"via properties cannot change",

Expected behavior

The error likely stems from this claim in the WAP

Servers SHOULD reject update requests that modify the values of the canonical or via properties, if they have been already set, unless business logic allows the request to be trusted as authoritatively correctly a previous error.

https://www.w3.org/TR/annotation-protocol/#update-an-existing-annotation

However, this should never trigger if the via field does NOT pre-exist.
This bug likely also concerns the canonical property

[github-actions]

Branch issue-65-PUT_Annotation_with_added_via_field_results_in_erronous_HTTP_409 created!