Download v3 pdb artifacts (#15856)

Author: mmitche

eng/publishing/v3/publish.yml

@@ -47,6 +47,20 @@ stages:
           **/MergedManifest.xml
         downloadPath: '$(Build.ArtifactStagingDirectory)/BlobArtifacts'
 
+    - task: DownloadPipelineArtifact@2
+      displayName: Download V3 PDB Artifacts
+      continueOnError: true
+      enabled: true
+      inputs:
+        buildType: specific
+        buildVersionToDownload: specific
+        project: $(AzDOProject)
+        pipeline: $(AzDOPipelineId)
+        buildId: $(AzDOBuildId)
+        downloadType: 'specific'
+        artifact: PdbArtifacts
+        downloadPath: '$(Build.ArtifactStagingDirectory)/PdbArtifacts'
+
     - task: DownloadPipelineArtifact@2
       displayName: Download V4 Merged Manifest
       continueOnError: true