Handle global tool specially when prepending PSHome to PATH

[daxian-dbw]

PR Summary

Fix #24090

Handle global tool specially when prepending PSHome to the PATH environment variable.
When running PowerShell global tool, the real entry executable should be the pwsh or pwsh.exe within the '../.dotnet/tools' folder, not what PSHome is pointing to.

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[daxian-dbw]

@adityapatwardhan I think we should not include the pwsh executable file in the any\unix and any\win folders, because there are only those 2 folders in the global tool, and you just cannot cover all the architecture flavors.

I guess the pwsh/pwsh.exe executable was added because there was complaint about $pshome\pwsh doesn't work? I think it's by design with the global tool installation. And with this change, the workaround would be to run pwsh directly which is guaranteed to be the same global tool executable (under .../.dotnet/tools)

[adityapatwardhan]

this is true for global tools that are installed globally with dotnet tool install -g. It can be installed to any path, but I agree that most people will install it globally. Maybe add this to comments.

[daxian-dbw]

Good point, thanks! I've updated the code to cover the scenario where the PowerShell global tool is installed to an arbitrary location.