PR Summary

Fixes #8919

Preserve user shortcuts pinned to Taskbar during MSI upgrade by not removing shortcuts in this case (assuming the user has not changed the installation directory), see https://stackoverflow.com/a/33402698/1810304
This also requires the Guid to not always be re-generated, which PR #7701 originally added to ensure shortcuts get removed when RTM and preview are installed, the underlying problem was rather that RTM and preview shared the same GUIDs, therefore the GUIDs are hard-coded again but different for RTM and preview, therefore the shortcuts will still always get removed on uninstall. But this also means those GUIDs should change when the default installation directory changes, i.e. in PowerShell 7. Should we write the code to already take this into account that it does not get forgotten?

Tested by first reproducing the issue by building installers locally (and bumping the patch version. Then the fix was applied to verify the solution, it. For this to take effect the version from which an MSI is being upgraded must have this fix already, i.e. if this fix got shipped in 6.2.1, then on ugrading to it, the issue would still occur but when upgrading 6.2.1 to 6.2.2 the shortcut would start being preserved. I am wondering if we could maybe improve this to show effect earlier by trying to extract the used (auto-generated) GUIDs in the 6.2.0 and 6.2.0-rc packages out and use them...
Please not that we probably need to take this out for 7.0 because the base installation directory will change. This also assumes that the user has not specified a different installation directory on upgrade but this is a bit of an edge case where I think other things might break as well.

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