Remove last_login and last_activity from $app.debugUserDiff.

html/src/app.js

@@ -1544,10 +1544,14 @@ speechSynthesis.getVoices();
                     props
                 });
                 if ($app.debugUserDiff) {
+                    delete props.last_login;
+                    delete props.last_activity;
+                    if (Object.keys(props).length !== 0) {
                         console.log('>', ref.displayName, props);
                     }
                 }
             }
+        }
         this.$emit('USER:APPLY', ref);
         return ref;
     };