PR#11367 Join-String causing build failures

[jsloan117]

Description

Since pulling in this change, our build pipelines failed with the error message below. I wonder how this isn't causing issues for others. Are people using PowerShell core for the build task, I double-checked the code and don't see pwsh: true being set.

C:\a\10\s\images.CI\linux-and-win\build-image.ps1 : The term 'Join-String' is not recognized as the name of a cmdlet, 
function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the 
path is correct and try again.

Platforms affected

• Azure DevOps
• GitHub Actions - Standard Runners
• GitHub Actions - Larger Runners

Runner images affected

• Ubuntu 20.04
• Ubuntu 22.04
• Ubuntu 24.04
• macOS 12
• macOS 13
• macOS 13 Arm64
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• Windows Server 2019
• Windows Server 2022
• [] Windows Server 2025

Image version and build link

latest images

Is it regression?

Before this PR

Expected behavior

For the images to build successfully.

Actual behavior

All of our pipelines are failing to build the images.

Repro steps

Attempt to build the image as is.