[release/10.0-preview3] Publish cross-apphost VS insertion packs

[jkoritzinsky]

main PR dotnet/arcade#15678

Description

The cross-apphost packs weren't being published. This ensures they are published correctly.

Customer Impact

This affects VS integration.

Regression

Yes

Testing

Manual validation of the final asset manifest

Risk

Low. This only adds publishing steps for assets that we were mistakenly not publishing. It does not remove any publishing steps nor does it change how we build anything

Package authoring no longer needed in .NET 9

IMPORTANT: Starting with .NET 9, you no longer need to edit a NuGet package's csproj to enable building and bump the version.
Keep in mind that we still need package authoring in .NET 8 and older versions.

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[jkoritzinsky]

We decided that we are okay for P3.