fix: Delete confusing assertion in test

The assertion implied that a version conflict can lead to a Right
value (maybe for either ElasticSearch or OpenSearch.) However, the
parsing logic would force this to be a Left value.

tests/Test/DocumentsSpec.hs

@@ -36,6 +36,7 @@ spec =
         insertedConflict <- tryEsError $ insertData' cfg
         case insertedConflict of
           Right (res', _) -> liftIO $ isVersionConflict res' `shouldBe` True
+          Right _ -> liftIO $ expectationFailure "This should never not happen."
           Left e -> liftIO $ errorStatus e `shouldBe` Just 409
 
     it "indexes two documents in a parent/child relationship and checks that the child exists" $