PackageProjectUrl should not be altered by the VMR build

[mmitche]

The package project url should point to the individual repo, rather than the VMR. For most repos, this doesn't matter because .NET release process won't release those packages, but it's a good idea to fix most of these

• Roslyn
• Templating
• Razor
• Roslyn-analyzers
• aspnetcore
• windowdesktop
• wpf
• deployment-tools
• vstest
• winforms
• symreader
• cecil

[mmitche]

To fix, we just need to set PackageProjectUrl in the above repos.

[mmitche]

Part of dotnet/wpf#10661

[Tanya-Solyanik]

WIndowsdesktop sets this property to a strange value - https://github.com/dotnet/windowsdesktop/blob/4788eed8178ec43e4360ef4424310ec934922833/Directory.Build.props#L8-#L9 - should it be updated as well?

[mmitche]

WIndowsdesktop sets this property to a strange value - https://github.com/dotnet/windowsdesktop/blob/4788eed8178ec43e4360ef4424310ec934922833/Directory.Build.props#L8-#L9 - should it be updated as well?

I think this is probably correct? This is probably a more general question about what .NET's package project URLs should point to.