Sync panel props to editing element (#470)

* ensure panel props are sync to editing elem

* ensure we don't create empty-text elements (fixes #468)

* remove dead code

Co-authored-by: Christopher Chedeau <vjeuxx@gmail.com>

src/scene/index.ts

@@ -5,7 +5,7 @@ export {
   deleteSelectedElements,
   someElementIsSelected,
   getElementsWithinSelection,
-  getSelectedAttribute
+  getCommonAttributeOfSelectedElements
 } from "./selection";
 export {
   exportCanvas,