[VS test] Increase test timeout (sonic-net#967)

*Increase test timeout to 240mts from 180mts
Signed-off-by: Sudharsan Dhamal Gopalarathnam <[email protected]>

Author: dgsudharsan

.azure-pipelines/test-docker-sonic-vs-template.yml

@@ -1,7 +1,7 @@
 parameters:
 - name: timeout
   type: number
-  default: 180
+  default: 240
 
 - name: log_artifact_name
   type: string