Remove duplicate @ prefix from issueAuthor in GitOps (#15636)

Author: Youssef1313

.github/policies/ScheduledSearch.MarkNoRecentActivity.yml

@@ -35,7 +35,7 @@ configuration:
               label: "State: No Recent Activity"
           - addReply:
               reply: >-
-                Hello @${issueAuthor},
+                Hello ${issueAuthor},
 
                 This pull request has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for **7 days**. It will be closed if no further activity occurs **within 7 days of this comment**.
       - description: >-
@@ -65,8 +65,8 @@ configuration:
               label: "State: No Recent Activity"
           - addReply:
               reply: >-
-                Hello @${issueAuthor},
+                Hello ${issueAuthor},
 
                 This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for **7 days**. It will be closed if no further activity occurs **within 7 days of this comment**.
 onFailure:
-onSuccess:
+onSuccess: