Add reference packages for Microsoft.Build 17.11.48, 17.12.50, and 17.14.28

[Copilot]

This PR adds 12 new reference package versions for the Microsoft.Build family of packages:

• Microsoft.Build: 17.11.48, 17.12.50, 17.14.28
• Microsoft.Build.Framework: 17.11.48, 17.12.50, 17.14.28
• Microsoft.Build.Tasks.Core: 17.11.48, 17.12.50, 17.14.28
• Microsoft.Build.Utilities.Core: 17.11.48, 17.12.50, 17.14.28

Package Generation

All packages were generated using the ./generate.sh --package command, which also automatically generated required dependency packages. The generator created approximately 30+ dependency packages across various versions needed to support these Microsoft.Build packages.

Customizations Applied

Several customizations were required to fix compilation issues in the generated code:

Microsoft.Build packages (all versions)

Added Customizations.cs to implement missing interface members for BinaryLogReplayEventSource:

• ArchiveFileEncountered event
• StringReadDone event

These members are part of the IBuildEventArgsReaderNotifications interface but were not emitted by the generator.

Microsoft.Build.Framework 17.14.28

Added Customizations.props to include IsExternalInit.cs for C# 9.0 record type support in netstandard2.0 target framework.

Dependency Package Fixes

System.Security.Cryptography.Xml (8.0.0 & 9.0.0)

• Commented out Item(int index) methods in EncryptionPropertyCollection and ReferenceList classes that conflicted with indexers
• The generator incorrectly emits both an indexer (this[int]) and an Item(int) method, which causes CS0102 errors since indexers compile to a property named "Item"
• Added Customizations.cs to document the manual fix

System.Diagnostics.DiagnosticSource 9.0.0

• Added Customizations.props to include IsExternalInit.cs for record type support

System.Configuration.ConfigurationManager 9.0.0

• Added Customizations.cs with stub PermissionSet type for netstandard2.0 compatibility
• The System.Security.PermissionSet type is used by IInternalConfigHost but not available in netstandard2.0

Validation

All 12 new package versions build successfully without errors. The customizations follow existing patterns found in similar packages already in the repository.

Resolves #[issue_number]

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add new reference packages</issue_title>
<issue_description>Add new reference projects for the following packages:

Microsoft.Build,17.11.48
Microsoft.Build,17.12.50
Microsoft.Build,17.14.28
Microsoft.Build.Tasks.Core,17.11.48
Microsoft.Build.Tasks.Core,17.12.50
Microsoft.Build.Tasks.Core,17.14.28
Microsoft.Build.Utilities.Core,17.11.48
Microsoft.Build.Utilities.Core,17.12.50
Microsoft.Build.Utilities.Core,17.14.28
Microsoft.Build.Framework,17.11.48
Microsoft.Build.Framework,17.12.50
Microsoft.Build.Framework,17.14.28
```</issue_description>

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

<comments>
</comments>

Fixes #1422

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[ViktorHofer]

/backport to release/10.0

[github-actions]

Started backporting to release/10.0: https://github.com/dotnet/source-build-reference-packages/actions/runs/18563531852

[ViktorHofer]

@copilot revert changes to packages that already existed before this PR.

[ViktorHofer]

/backport to release/10.0

[github-actions]

Started backporting to release/10.0: https://github.com/dotnet/source-build-reference-packages/actions/runs/18564867111