Return a more actionable error description when the user attempts to write to an MSIX-installation's root.

Summary of the new feature / enhancement

I want to execute any of the commands that learn.microsoft.com/en-us/powershell/scripting/install/installing-powershell-on-windows?view=powershell-7.5#known-limitations disallows: ^1

  [1]: https://github.com/PowerShell/PowerShell/discussions/25729#discussioncomment-13676474

1. Register-PSSessionConfiguration

2. Update-Help -Scope AllUsers

3. Enable-ExperimentalFeature -Scope AllUsers

4. Set-ExecutionPolicy -Scope LocalMachine

As an example, when I invoke Set-ExecutionPolicy -Scope LocalMachine, I see similar to:

Access to the path '$Env:ProgramFiles\WindowsApps\Microsoft.PowerShellPreview_7.6.4.0_x005F_x64__8wekyb3d8bbwe\powershell.config.json' is denied. To change the execution policy for the default (LocalMachine) scope, start PowerShell with the "Run as administrator" option. To change the execution policy for the current user, run "Set-ExecutionPolicy -Scope CurrentUser".

Considering that PowerShell knows that it's been installed with Add-AppxPackage, it knows the cause of this. Consequently, the user should be informed of the reason, or it should cite the relevant documentation.

Proposed technical implementation details (optional)

No response

Start with the four commands listed in the issue and the linked MSIX known-limitations documentation, then trace how each reports denied writes under the WindowsApps installation root. Done means affected commands provide an actionable explanation of the MSIX restriction or point users to the relevant documentation.