fix: copy+paste persisting invalid, transient attribute

To repro, copy and paste block(s) in a db graph

src/main/frontend/util.cljc

@@ -858,7 +858,7 @@
                  (common-util/remove-nils-non-nested
                   {:text text
                    :html html
-                   :blocks (when (seq blocks) (pr-str blocks))}))]
+                   :blocks (when (seq blocks) (pr-str (mapv #(dissoc % :block.temp/fully-loaded? %) blocks)))}))]
        (if owner-window
          (utils/writeClipboard data owner-window)
          (utils/writeClipboard data)))))