use preparation instead of installing scripts/vsts

Author: aminya

script/vsts/nightly-release.yml

@@ -33,11 +33,6 @@ jobs:
     steps:
       - template: platforms/templates/preparation.yml
 
-      - script: |
-          cd script/vsts
-          npm install
-        displayName: npm install
-
       - task: DownloadBuildArtifacts@0
         inputs:
           itemPattern: '**'

script/vsts/release-branch-build.yml

@@ -38,13 +38,6 @@ jobs:
     steps:
       - template: platforms/templates/preparation.yml
 
-      - script: |
-          cd script/vsts
-          npm install
-        env:
-          GITHUB_TOKEN: $(GITHUB_TOKEN)
-        displayName: npm install
-
       - task: DownloadBuildArtifacts@0
         inputs:
           itemPattern: '**'