Update dependencies to latest for v5 major release

[Shazwazza]

Since we're shipping a new major version, this bumps all NuGet and npm dependencies to their latest stable releases so v5 starts on a current baseline.

Changes

• Microsoft.SourceLink.GitHub 8.0.0 -> 10.0.301
• Microsoft.Extensions.* (Configuration, Configuration.Json, FileProviders.Composite, Hosting.Abstractions, Logging.Abstractions, Options) 10.0.9 -> 10.0.10
• xunit 2.7.0 -> 2.9.3
• xunit.runner.visualstudio 2.5.7 -> 3.1.5
• Microsoft.NET.Test.Sdk 17.9.0 -> 18.8.1
• Moq 4.20.70 -> 4.20.72
• uglify-js (Web sample) ^2.7.0 -> ^3.19.3

Notes

• Nuglify (1.22.0) and Dazinator.Extensions.FileProviders (2.0.0) were already on their latest stable versions; newer releases are prerelease only, so they were left untouched.
• Stayed on stable releases rather than the 11.0 previews, consistent with the repo already targeting stable net10.0 packages.
• Removed the long-deprecated dotnet-xunit CLI tool reference while bumping xunit, since it is incompatible with modern xunit runners.

Validation

Build succeeds with zero warnings (the repo has TreatWarningsAsErrors enabled) and all tests pass (65 unit + 24 integration = 89 total).