Indicate in the Assets file when Package Source Mapping was enabled

[donnie-msft]

NuGet Product(s) Affected

NuGet.exe, Visual Studio Package Management UI, Visual Studio Package Manager Console, MSBuild.exe, dotnet.exe, NuGet SDK

Current Behavior

The assets file does not log any indication of whether Package Source Mapping was used during the restore. When investigating a customer's binlog, for example, the only way to know this status is to ask the customer.

Desired Behavior

Similar to how other features are recorded in the assets file, eg,

"centralPackageVersionsManagementEnabled": true,
"CentralPackageTransitivePinningEnabled": true,

Add something like this to the assets file:
"PackageSourceMappingEnabled": true,

Additional Context

No response

[nkolev92]

Since it's internal tweaking the label to bug since DCR will get flagged in the release notes.