Fix: Don't change working directory when invoking tsp-client

[Copilot]

Problem

PR #52973 introduced a change that uses Push-Location to change the working directory to eng/common/tsp-client before invoking tsp-client. This causes issues because tsp-client makes assumptions based on the current working directory where it's executed.

Solution

This PR keeps Push-Location/Pop-Location for npm ci (which requires running from the tsp-client directory) but executes tsp-client using npm exec --prefix instead of running it from within the changed directory. This ensures:

1. npm dependencies are installed correctly from the tsp-client directory
2. tsp-client runs from the current working directory where it makes its assumptions
3. The pinned tsp-client version from eng/common/tsp-client is used

Changes

Before:

Push-Location $tspClientDir
try {
    npm ci
    $tspclientCommand = "npm exec --no -- tsp-client init ..."
    Invoke-Expression $tspclientCommand
}
finally {
    Pop-Location
}

After:

Push-Location $tspClientDir
try {
    npm ci
}
finally {
    Pop-Location
}

$tspclientCommand = "npm exec --prefix $tspClientDir --no -- tsp-client init --update-if-exists ..."
Invoke-Expression $tspclientCommand

This ensures that tsp-client runs from the correct working directory where it can properly resolve paths and make its assumptions, while still using the pinned version from eng/common/tsp-client.

Fixes #53155

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Don't change working directory in Invoke-GenerateAndBuildV2.ps1</issue_title>
<issue_description>#52973 changed the working directory before invoking tsp-client. This is a problem as tsp-client makes assumptions based on working directory. We need to just pass the path to the tsp-client to invoke.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #53155

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[Copilot]

Pull Request Overview

This PR fixes a working directory issue in the PowerShell script Invoke-GenerateAndBuildV2.ps1 where the script was changing the working directory before invoking tsp-client, which caused problems because tsp-client makes assumptions based on the current working directory.

Key changes:

• Removed the Push-Location/Pop-Location pattern that was changing the working directory
• Used npm's --prefix option to specify the target directory without changing the current working directory
• Maintained the same functionality while avoiding the working directory change issue

[JoshLove-msft]

/check-enforcer evaluate