handle corner case of content rule of changing id on cut/paste (#4559)

plone/dexterity/utils.py

@@ -171,7 +171,10 @@ def addContentToContainer(container, object, checkConstraints=True):
         if HAS_UUID:
             # work around edge case where a content rule may have moved the item
             uuid = IUUID(object)
-            return uuidToObject(uuid)
+            try:
+                return uuidToObject(uuid)
+            except KeyError:
+                return None
         else:
             # no way to know where it is
             raise