[release/7.0-rc1] Add NuGet package for System.Runtime.Serialization.Schema #74597
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Backport of #74533 to release/7.0-rc1
/cc @carlossanlop @eerhardt
Customer Impact
System.Runtime.Serialization.Schema isn't getting a NuGet package created for it because it doesn't set IsPackable=true.
Testing
Risk
IMPORTANT: Is this backport for a servicing release? If so and this change touches code that ships in a NuGet package, please make certain that you have added any necessary package authoring and gotten it explicitly reviewed.