customization task "install-vs-extension" cannot install GitHub Copilot

[luxu-ms]

Describe the bug
The dev box customization task "install-vs-extension" cannot work well

To Reproduce
Steps to reproduce the behavior:

1. Use the base image "Visual Studio 2022 Enterprise on Windows 11 Enterprise + Microsoft 365 Apps 23H2"
2. Create the dev box using the base image in step 1 and upload the yaml file as below:

3. Login to the dev box and open VS
   Actual result:
   VS extension GitHub Copilot is NOT installed.

Expected behavior
VS extension GitHub Copilot is installed.

Screenshots

Dev Box VM Details (please complete the following information):

• OS version: Visual Studio 2022 Enterprise on Windows 11 Enterprise + Microsoft 365 Apps 23H2

Additional context
This is because when dev box task is triggered, system role is used.
When the user is system role, the vsix file will be downloaded under C:\Windows\System32\config\systemprofile
When VSIXInstaller.exe want to use this vsix file, it cannot find the vsix file. Because the vsix file is under limited directory.
Suggestion: When downloading the vsix file, put it under other normal folder like "C:\temp-vsix" instead of [IO.Path]::GetTempPath()