Changedetection.io: Skip checking for diff if watch never had a change (#2186)

* Only check diff in there has ever been a change

* Code style

---------

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/widgets/changedetectionio/component.jsx

@@ -28,7 +28,7 @@ export default function Component({ service }) {
   let diffsDetected = 0;
 
   Object.keys(data).forEach((key) => {
-    if (data[key].last_checked === data[key].last_changed) {
+    if (data[key].last_changed > 0 && data[key].last_checked === data[key].last_changed) {
       diffsDetected += 1;
     }
   });