Unpin System.Formats.Asn1 Package Version

[lonitra]

Unpin System.Formats.Asn1 package version from versions.prop when NuGet.Packaging upgrades to use non vulnerable System.Formats.Asn1 package version

[ericstj]

cc @zivkan

[zivkan]

<troll>blocked on dotnet/runtime#105028 </troll> 😆

But seriously, I fixed this in NuGet/NuGet.Client#5939, so will be fixed with NuGet's 6.12.* packages.