Fix generation task drop folder issue (#23910)

Author: vidai-msft

.azure-pipelines/code-oob.yml

@@ -131,7 +131,7 @@ stages:
       displayName: 'Generation Task'
       inputs:
         PackageName: 'Azure PowerShell - ${{ parameters.ServiceName }}'
-        BuildDropPath: '$(System.ArtifactsDirectory)/OOB'
+        BuildDropPath: OOB
 
     - task: PublishBuildArtifacts@1
       inputs:

.azure-pipelines/sign-tool-installer.yml

@@ -71,7 +71,7 @@ steps:
   displayName: 'Generation Task'
     inputs:
       PackageName: 'Azure PowerShell - Az Tools Installer'
-      BuildDropPath: '$(System.ArtifactsDirectory)/artifacts'
+      BuildDropPath: artifacts
 
 - task: PublishPipelineArtifact@0
   displayName: 'Save artifacts'