Update time and description of 3.4.6

Author: github-actions[bot]

Update.json

@@ -3576,7 +3576,7 @@
             "Notes": "Fix loginpage.php loop."
         },
         "3.4.6": {
-            "UpdateDate": 1777707927028,
+            "UpdateDate": 1777708038758,
             "Prerelease": true,
             "UpdateContents": [
                 {