[Blazor] Compute _BlazorJSFile for _ReplaceFingerprintedBlazorJsForPublish

[maraf]

When Blazor Wasm project is referenced from an AspNetCore server project, we need to compute _BlazorJSFile to correctly replace StaticWebAssets _ReplaceFingerprintedBlazorJsForPublish.

To mitigate that the Server project already contains assets for blazor.js from build (and removing them inside of the nested build isn't enough), we define the SWA for blazor.js AssetKind=Build and AssetKind=Publish if fingerprinting is enabled.

This needs to be backported to .NET 10.

Fixes dotnet/runtime#119886

[github-actions]

This PR is targeting main, which is now for .NET 11-facing work. If you intended to target .NET 10, either retarget this PR to release/10.0.1xx or make sure you backport the change to release/10.0.1xx after merging. See #50394 for more details.

[Copilot]

Pull Request Overview

This PR fixes an issue with fingerprinted Blazor JS file replacement when a Blazor WebAssembly project is referenced from an ASP.NET Core server project. The fix ensures proper computation of _BlazorJSFile and modifies the static web asset handling to prevent asset conflicts during the publish process.

• Refactors _BlazorJSFile computation into a separate target for better dependency management
• Modifies asset kind handling to use Build for fingerprinted assets and Publish for replacement assets
• Adds comprehensive test coverage for both fingerprinted and non-fingerprinted scenarios

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

File	Description
src/BlazorWasmSdk/Targets/Microsoft.NET.Sdk.BlazorWebAssembly.6_0.targets	Core fix - refactors JS file resolution and asset kind handling for proper fingerprinting
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/WasmPublishIntegrationTest.cs	Adds test method to verify the fix works for both fingerprinted and non-fingerprinted scenarios
test/TestAssets/TestProjects/BlazorWasmReferencedByAspNetCoreServer/*	Complete test project structure with server and client projects to reproduce the issue

[maraf]

/backport to release/10.0.1xx

[github-actions]

Started backporting to release/10.0.1xx: https://github.com/dotnet/sdk/actions/runs/17882989747

[javiercn]

Changes look good. One question that I had is, doesn't the original repro include a PWA? I'm curious as to why this scenario failed and other similar scenarios on the tests didn't.

What's special about this asset configuration?

[maraf]

The original repro contained PWA, but the failure was happening without it as well.

I'm not sure if test Blazor Wasm referenced by AspNetCore server and doing publish.

[maraf]

Closed in favor of #50949