Pin implicit SDK pack versions

[Kamilr616]

What changed

• removes explicit references to SDK-owned ILLink and WebAssembly pack packages,
• pins their versions through a target that runs immediately before ProcessFrameworkReferences,
• preserves the existing cross-platform lock file versions required by the pinned .NET SDK.

Why

The explicit Microsoft.NET.ILLink.Tasks reference made locked restore deterministic across Windows and Linux, but the SDK warns that explicit references to this package can cause versioning problems during publish. Updating the SDK-owned pack metadata retains deterministic restore without treating SDK implementation packages as application dependencies.

Validation

• locked restore passed,
• formatting verification passed,
• Release build passed with warnings treated as errors,
• 34/34 tests passed,
• Release publish passed with warnings treated as errors,
• the previous explicit ILLink package warning is no longer emitted.

[Copilot]

Pull request overview

This PR updates the Blazor WASM client project to keep restore deterministic under locked mode while avoiding explicit references to SDK-implementation packages (which can cause publish-time SDK warnings and versioning issues).

Changes:

• Removed explicit PackageReference entries for Microsoft.NET.ILLink.Tasks and Microsoft.NET.Sdk.WebAssembly.Pack.
• Added an MSBuild target that pins the SDK-owned pack versions via KnownILLinkPack / KnownWebAssemblySdkPack updates before ProcessFrameworkReferences.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.