Add feature to detect and reset NoImpersonate flag on .MSI files that won't work well with UAC in Vista/Win7

From https://code.google.com/p/lessmsi/issues/detail?id=3

> See the following article: http://hunter555.blogspot.com/2007/02/installer-error-code-2869-msi-and-uac.html
>
> Interesting idea. Lessmsi maybe needs another suite of tools or a utility for
> modifying msi files. Currently it is only readonly, but I can see how this stuff
> is useful.
>
> melnikov.alex
> yes, modifying some flags directly, without rebuilding msi would be a good feature.
> //alex

No files or tests are named in the issue. Start by identifying the project’s CLI entrypoint and the C# MSI parsing/writing logic, since the request is to make the flow detect and clear a NoImpersonate flag. Check whether MSI handling is currently read-only, then locate where to add a writable path and flag mutation. Scope is complete when there is a reproducible check for the flag and a documented/verified reset path that doesn’t break extraction behavior.

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