FIX: Updating guardian files 18-12-2025 (#381)

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[AB#41192](https://sqlclientdrivers.visualstudio.com/c6d89619-62de-46a0-8b46-70b92a84d85e/_workitems/edit/41192)

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### Summary   
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required. -->
This pull request primarily updates `.gdn` baseline and suppression
files to add a new signature entry and refreshes timestamps.
Additionally, it refines the GitHub-Azure DevOps sync pipeline to better
handle `.gdn` files during repository synchronization.

**.gdn Baseline and Suppression Updates:**

* Added a new signature entry
(`b193001ba0796417acfe030647f04db3d4a9a561f580338977d8f68230b5c20c`) to
both `.gdn/.gdnbaselines` and `.gdn/.gdnsuppress`, associating it with
the `default` group and updating the `lastUpdatedDate` fields.
[[1]](diffhunk://#diff-9246ddd12574f37c19831129f642cc5bb2920110c54825563be451a4808f9fc3L11-R11)
[[2]](diffhunk://#diff-9246ddd12574f37c19831129f642cc5bb2920110c54825563be451a4808f9fc3R386-R393)
[[3]](diffhunk://#diff-a7fdb3f611082ade077d9a6aef98db36c848387741e8a41a26ffa800a5993421L11-R11)
[[4]](diffhunk://#diff-a7fdb3f611082ade077d9a6aef98db36c848387741e8a41a26ffa800a5993421R386-R393)

**Pipeline Improvements:**

* Modified the `github-ado-sync.yml` pipeline so that `.gdn` files are
excluded when removing and checking out files, preventing accidental
deletion or overwriting of `.gdn` configuration during sync.

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Author: gargsaumya

.gdn/.gdnbaselines

@@ -8,7 +8,7 @@
     "default": {
       "name": "default",
       "createdDate": "2025-11-10 15:00:51Z",
-      "lastUpdatedDate": "2025-12-15 10:23:22Z"
+      "lastUpdatedDate": "2025-12-18 10:54:41Z"
     }
   },
   "results": {
@@ -383,6 +383,14 @@
         "default"
       ],
       "createdDate": "2025-12-15 10:23:22Z"
+    },
+    "b193001ba0796417acfe030647f04db3d4a9a561f580338977d8f68230b5c20c": {
+      "signature": "b193001ba0796417acfe030647f04db3d4a9a561f580338977d8f68230b5c20c",
+      "alternativeSignatures": [],
+      "memberOf": [
+        "default"
+      ],
+      "createdDate": "2025-12-18 10:54:41Z"
     }
   }
 }

.gdn/.gdnsuppress

@@ -8,7 +8,7 @@
     "default": {
       "name": "default",
       "createdDate": "2025-11-10 15:00:51Z",
-      "lastUpdatedDate": "2025-12-15 10:23:22Z"
+      "lastUpdatedDate": "2025-12-18 10:54:41Z"
     }
   },
   "results": {
@@ -383,6 +383,14 @@
         "default"
       ],
       "createdDate": "2025-12-15 10:23:22Z"
+    },
+    "b193001ba0796417acfe030647f04db3d4a9a561f580338977d8f68230b5c20c": {
+      "signature": "b193001ba0796417acfe030647f04db3d4a9a561f580338977d8f68230b5c20c",
+      "alternativeSignatures": [],
+      "memberOf": [
+        "default"
+      ],
+      "createdDate": "2025-12-18 10:54:41Z"
     }
   }
 }