Change hardcoded value to variable

Variable threshold was unused and variable windowEnd was hard-coded to TimeGenerated+5m.

Hunting Queries/AzureStorage/AzureStorageFileCreatedQuicklyDeleted.yaml

@@ -31,10 +31,10 @@ query: |
       | project OperationName, DeletedTime=TimeGenerated, Uri
   ) on Uri
   | project TimeGenerated, DeletedTime, Uri, CallerIpAddress, UserAgentHeader, ResponseMd5, StorageAccount=AccountName
-  | extend windowEnd = TimeGenerated+5m 
+  | extend windowEnd = TimeGenerated+threshold 
   | where DeletedTime between (TimeGenerated .. windowEnd)
 entityMappings:
   - entityType: IP
     fieldMappings:
       - identifier: Address
-        columnName: CallerIpAddress
+        columnName: CallerIpAddress