Revert change to editor GUID

We will use the same GUID for the new editor now that this one has been removed.

Author: drewnoakes

src/Microsoft.VisualStudio.AppDesigner/Resources/Designer.Designer.vb

@@ -233,7 +233,7 @@
     <value>Change property: {0}</value>
   </data>
   <data name="ResourceEditorFactory_GUID" xml:space="preserve">
-    <value>81828910-b8b3-4d2b-99a3-067027c180c1</value>
+    <value>ff4d6aca-9352-4a5f-821e-f4d6ebdcab11</value>
     <comment>{Locked}</comment>
   </data>
   <data name="SettingsDesignerEditorFactory_GUID" xml:space="preserve">