Fix typo (correct 'enpty' to 'empty') (#1133)

appinventor/appengine/src/com/google/appinventor/client/OdeMessages.java

@@ -6231,7 +6231,7 @@ public interface OdeMessages extends Messages {
 
   @DefaultMessage("<p>It appears that <b>" + "%1" +
       "</b> has had all blocks removed.</p><p>" +
-      "<ul><li>You can save the enpty screen, and then all those blocks will be " +
+      "<ul><li>You can save the empty screen, and then all those blocks will be " +
       "permanently gone from the project.</li>" +
       "<li>Alternatively, you can restore the previously saved version " +
       "of the project.</li></ul></p>")