Sync eng/common directory with azure-sdk-tools for PR 2685 (Azure#20222)

* Fixed the no IsPrerelease property issue and retry 3 times on API call.

* check null

Co-authored-by: sima-zhu <sizhu@microsoft.com>

Author: azure-sdk

eng/common/scripts/Helpers/Metadata-Helpers.ps1

@@ -30,7 +30,7 @@ function GetMsAliasFromGithub ($TenantId, $ClientId, $ClientSecret, $GithubUser)
         $opsAuthToken = Generate-AadToken -TenantId $TenantId -ClientId $ClientId -ClientSecret $ClientSecret
         $Headers["Authorization"] = "Bearer $opsAuthToken"
         Write-Host "Fetching aad identity for github user: $GithubUser"
-        $resp = Invoke-RestMethod $OpensourceAPIBaseURI -Method 'GET' -Headers $Headers
+        $resp = Invoke-RestMethod $OpensourceAPIBaseURI -Method 'GET' -Headers $Headers -MaximumRetryCount 3
     }
     catch { 
         Write-Warning $_

eng/common/scripts/Update-DocsMsMetadata.ps1

@@ -180,9 +180,12 @@ function UpdateDocsMsMetadataForPackage($packageInfoJsonLocation, $packageInfo)
   }
 
   # Copy package info file to the docs repo
+  $docsMsMetadata = &$GetDocsMsMetadataForPackageFn $packageInfo
+  $readMePath = $docsMsMetadata.LatestReadMeLocation
   $metadataMoniker = 'latest'
-  if ($originalVersion.IsPrerelease) {
+  if ($originalVersion -and $originalVersion.IsPrerelease) {
     $metadataMoniker = 'preview'
+    $readMePath = $docsMsMetadata.PreviewReadMeLocation
   }
   $packageMetadataName = Split-Path $packageInfoJsonLocation -Leaf
   $packageInfoLocation = Join-Path $DocRepoLocation "metadata/$metadataMoniker"
@@ -203,11 +206,6 @@ function UpdateDocsMsMetadataForPackage($packageInfoJsonLocation, $packageInfo)
   if ($readmeContent) { 
     $outputReadmeContent = GetAdjustedReadmeContent $readmeContent $packageInfo $packageMetadata
   }
-  $docsMsMetadata = &$GetDocsMsMetadataForPackageFn $packageInfo
-  $readMePath = $docsMsMetadata.LatestReadMeLocation
-  if ($originalVersion.IsPrerelease) { 
-    $readMePath = $docsMsMetadata.PreviewReadMeLocation
-  }
 
   $suffix = $docsMsMetadata.Suffix
   $readMeName = "$($docsMsMetadata.DocsMsReadMeName.ToLower())-readme${suffix}.md"