Raise before trying to access status

In case of an error the returned object does not respond to
`#status`.

Author: oneiros

fasp_data_sharing/app/models/fasp_data_sharing/activity_pub_object.rb

@@ -8,9 +8,11 @@ class FaspDataSharing::ActivityPubObject
 
   def fetch
     response = message_signature_request
-    response = signature_request if response.status.in?([ 401, 403 ])
 
     response.raise_for_status
+
+    response = signature_request if response.status.in?([ 401, 403 ])
+
     JSON.parse(response.body.to_s) # TODO: simplify with response.json after next httpx release
   end