allow download sonic-swss-common.amd64.ubuntu20_04 from partially succeeded builds

Author: qiluo-msft

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

@@ -28,6 +28,7 @@ jobs:
       artifact: sonic-swss-common.amd64.ubuntu20_04
       runVersion: 'latestFromBranch'
       runBranch: 'refs/heads/202106'
+      allowPartiallySucceededBuilds: true
     displayName: "Download sonic swss common deb packages"
 
   - script: |