fix(ci): unblock main — SourceLink 10.0.401 + IDE0370

[Tiberriver256]

Summary

Main (and every Dependabot PR based on it) is red because Cake Restore/Build fails for two independent reasons:

1. NU1902 (restore) — Microsoft.SourceLink.GitHub 10.0.300 pulls Microsoft.Build.Tasks.Git 10.0.300, which is flagged by GHSA-23fw-v26w-5fgq / CVE-2026-62900. With TreatWarningsAsErrors, restore fails. Introduced by merging Bump Microsoft.SourceLink.GitHub from 10.0.102 to 10.0.300 #176; advisory published 2026-09-08.
2. IDE0370 (compile) — unnecessary ! on JsonValue.Create(...) in ODataQueryOptionsDocumentFilter.cs becomes an error under AnalysisLevel=latest + TreatWarningsAsErrors (from the Health TOP5: deps, quality gates, ValidationHarness in CI, multi-target, hygiene #177 health work).

Evidence: local dotnet cake --target=Build on current main fails with NU1902; after SourceLink-only bump, restore passes and build fails IDE0370. Both fixed here → Build/Test/coverage/Pack succeed locally (17 tests, ~34% coverage ≥ 30% gate).

CodeQL Analyze fails for the same autobuild/restore reason.

Changes

• Bump Microsoft.SourceLink.GitHub 10.0.300 → 10.0.401 in Source/Directory.Build.props and the project Update
• Drop four unnecessary null-forgiving operators (IDE0370)

After merge

Rebase/rerun Dependabot PRs. Expected to go green (patch/minor, non-major):

• chore(deps): bump github/codeql-action from 4.35.4 to 4.37.9 #180 codeql-action
• chore(deps): bump release-drafter/release-drafter from 7.3.0 to 7.7.0 #182 release-drafter
• Bump Microsoft.AspNetCore.OData from 9.4.1 to 9.5.0 #183 AspNetCore.OData 9.5.0
• Bump Microsoft.EntityFrameworkCore.InMemory from 10.0.2 to 10.0.12 #184 EF Core InMemory
• Bump Microsoft.OData.Core and Microsoft.OData.Edm #185 OData.Core/Edm
• Bump Microsoft.OpenApi from 3.5.5 to 3.10.2 #186 OpenApi 3.10.2
• Bump Microsoft.SourceLink.GitHub from 10.0.300 to 10.0.401 #187 SourceLink (becomes no-op / close after this)
• Bump MSTest.Analyzers from 4.2.2 to 4.4.0 #189 MSTest.Analyzers
• Bump Swashbuckle.AspNetCore from 10.1.7 to 10.2.3 #190 Swashbuckle.AspNetCore example
• Bump Swashbuckle.AspNetCore.Swagger and Swashbuckle.AspNetCore.SwaggerGen #192 Swagger + SwaggerGen

Do not merge majors without approval: #179 checkout v7, #181 setup-dotnet v6, #188 MinVer 8, plus older #152/#162.

Test plan

• Local Cake Build/Test/Pack on this branch
• CI Build matrix + CodeQL Analyze green on this PR
• After merge, re-run a sample Dependabot PR (e.g. Bump Microsoft.OData.Core and Microsoft.OData.Edm #185)