feat: Add prop UIOptions.canvasActions.saveAsImage to show/hide save image button (#3662)

* feat: Add prop UIOptions.canvasActions.saveAsImage which implies whether the save as image dialog should be shown

* Add docs

* fix specs

src/components/LayerUI.tsx

@@ -401,7 +401,7 @@ const LayerUI = ({
   };
 
   const renderImageExportDialog = () => {
-    if (!UIOptions.canvasActions.export) {
+    if (!UIOptions.canvasActions.saveAsImage) {
       return null;
     }