[PowerToys] Extract MSI from EXE for WiX v5

[davidegiacometti]

Updated the doc with instruction for extracting MSI from EXE for version 0.94 and later (using WiX Toolset v5).

PS C:\Users\david> wix burn extract ${Env:\USERPROFILE}"\Desktop\PowerToysSetup-0.94.0-x64.exe" -out ${Env:\USERPROFILE}"\Desktop\extractedPath" -oba ${Env:\USERPROFILE}"\Desktop\extractedPath"
PS C:\Users\david> ls -l ${Env:\USERPROFILE}\Desktop\extractedPath\WixAttachedContainer\PowerToysSetup-0.94.0-wix5-x64.msi

    Directory: C:\Users\david\Desktop\extractedPath\WixAttachedContainer

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
-a---          29/08/2025    22:01      318943232 PowerToysSetup-0.94.0-wix5-x64.msi

[prmerger-automator]

@davidegiacometti : Thanks for your contribution! The author(s) and reviewer(s) have been notified to review your proposed change.

[learn-build-service-prod]

Learn Build status updates of commit d5496f4:

✅ Validation status: passed

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[learn-build-service-prod]

Learn Build status updates of commit 3c2e29d:

✅ Validation status: passed

File	Status	Preview URL	Details
hub/powertoys/install.md	✅Succeeded

For more details, please refer to the build report.