Update build directory clean up stage for python package pipeline (#19553)

Fix to make clean up stage take effect.

If the `SourceFolder ` is empty, the task deletes files from the root
folder of the repository as though
[$(Build.SourcesDirectory)](https://learn.microsoft.com/en-us/azure/devops/pipelines/build/variables)
was specified.

tools/ci_build/github/azure-pipelines/templates/component-governance-component-detection-steps.yml

@@ -5,10 +5,12 @@ parameters:
   default: 'succeeded' # could be 'ci_only', 'always', 'succeeded'
 
 steps:
-- ${{ if eq(variables['System.TeamProject'], 'Lotus') }}: 
+- ${{ if eq(variables['System.TeamProject'], 'Lotus') }}:
   - task: DeleteFiles@1
     inputs:
-      contents: $(Build.BinariesDirectory)/*
+      SourceFolder: '$(Build.BinariesDirectory)'
+      contents: |
+        **/*
     displayName: 'Clean up build directory'
 
   - task: ms.vss-governance-buildtask.governance-build-task-component-detection.ComponentGovernanceComponentDetection@0