Make Sandbox script work in PowerShell 5

[mdanish-kh]

List of stuff not supported in PS5:

• Ternary operator (?)
• -AdditionalPath param for Join-Path cmdlet
• Doesn't support piping into Write-Information
• Requires the assembly to be loaded before using it (either with using assembly System.Net.Http or Add-Type)

Manually validated that the script works with the changes.

• Closes Add requires statement to SandboxTest.ps1 #247863 (if that doesn't get merged first :D)

cc @Trenly @jedieaston

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Microsoft Reviewers: Open in CodeFlow

[wingetbot]

   

[mdanish-kh]

[Policy] Needs-Manual-Merge

[jedieaston]

Thanks!