Add MSBuild reference packages version 17.8.43

[Copilot]

This PR adds version 17.8.43 of the following MSBuild reference packages to the release/9.0 branch:

• Microsoft.Build
• Microsoft.Build.Tasks.Core
• Microsoft.Build.Utilities.Core
• Microsoft.Build.Framework

Changes

All packages were generated using the generate.sh script following the standard repository workflow. The generation process also created the following dependency packages:

• Microsoft.NET.StringTools 17.8.43
• Microsoft.VisualStudio.Setup.Configuration.Interop 3.2.2146

All new packages have been added to eng/Build.props in the correct dependency order, ensuring they build before packages that depend on them.

Regenerated Package Fixes

During generation, some existing packages were regenerated as dependencies. Intentional manual modifications to these packages have been preserved:

System.Runtime.InteropServices

Retained the System.Runtime.InteropServices.Manual.cs file containing the ComAwareEventInfo partial class, which is needed to address dotnet/source-build#4000.

System.Security.Cryptography.Xml

Restored [System.Runtime.CompilerServices.IndexerName("ItemOf")] attributes on indexer properties in the EncryptionPropertyCollection and ReferenceList classes. These attributes are manually added because GenAPI filters them out, and they are required to prevent conflicts between the indexer properties (this[int index]) and the Item(int index) methods.

System.Configuration.ConfigurationManager

Restored #pragma warning disable/restore SYSLIB0003 directives around methods using the obsolete PermissionSet type. These pragmas suppress compiler warnings while maintaining API compatibility.

Verification

All packages build successfully with the source-build configuration:

./build.sh -sb

All 6 new packages are generated in the artifacts directory and included in the intermediate source-build package.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add MSBuild reference packages</issue_title>
<issue_description>Add version 17.8.43 of the following packages to the release/9.0 branch:

Microsoft.Build
Microsoft.Build.Tasks.Core
Microsoft.Build.Utilities.Core
Microsoft.Build.Framework</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #1429

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[ViktorHofer]

Logging off. @dotnet/source-build can you please take a look and approve and merge if the changes look correct? Thanks

cc @PranavSenthilnathan