chore(deps): Keep risky majors out of the NuGet group, move Testcontainers together

[mpaulosky]

Why

The recreated Dependabot group PR #128 fails, and would be risky even once it builds:

Package	#128	Problem
Testcontainers	4.7.0 → 4.15.0	Testcontainers.MongoDb/.Redis left on 4.7.0. Build fails (UntilPortIsAvailable removed), and after that all 54 Mongo integration tests fail with MissingMethodException.
Radzen.Blazor	7.3.2 → 11.4.1	Four majors. 16 bUnit tests fail (Radzen.createDataGrid JS call). Component and theme changes need a manual UI check.
MessagePack	2.5.302 → 3.1.9	Pinned only to force a patched transitive version. Aspire's StreamJsonRpc 2.25.29 is built against 2.5.302, so a forced 3.x risks runtime failures in the AppHost that Dependabot PRs don't test.

What

.github/dependabot.yml (nuget):

• ignore semver-major updates of Radzen.Blazor and MessagePack. Minor and patch updates still come through.
• New testcontainers group (Testcontainers*) ahead of all-nuget, so the core and its modules always move together.

Testcontainers aligned now: Testcontainers, .MongoDb and .Redis go to 4.15.0. IssueTrackerTestFactory switches to UntilInternalTcpPortIsAvailable, the 4.15 name for the same wait.

Validation

• dotnet build -c Release: 0 errors.
• Every test project except AppHost.Tests (418 of 418 pass), including PlugIns integration (54, against a real Mongo container).
• yamllint clean on dependabot.yml.

After merge

@dependabot recreate on #128. It should come back without the Radzen and MessagePack majors or Testcontainers. The Radzen 11 upgrade gets its own PR.

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🟢 Approval recommended

The dependency alignment, API migration, and Dependabot rules are internally consistent and valid.

Review effort: Balanced
Findings: None

What changed in this PR

Aligns Testcontainers dependencies and prevents risky major upgrades from entering grouped Dependabot PRs.

Changes:

• Aligns all Testcontainers packages at 4.15.0.
• Migrates to the renamed internal-port wait API.
• Separates Testcontainers updates and excludes risky majors.

File	Description
.github/​dependabot.yml	Adds exclusions and a Testcontainers group.
Directory.Packages.props	Aligns Testcontainers package versions.
tests/​IssueTracker.PlugIns.Tests.Integration/​IssueTrackerTestFactory.cs	Updates the wait-strategy API call.

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[github-actions]

Test Results Summary

412 tests  ±0   412 ✅ ±0   15s ⏱️ +3s
  8 suites ±0     0 💤 ±0 
  8 files   ±0     0 ❌ ±0 

Results for commit 83b47f9. ± Comparison against base commit acd1bef.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.59%. Comparing base (acd1bef) to head (83b47f9).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #132   +/-   ##
=======================================
  Coverage   85.59%   85.59%           
=======================================
  Files          77       77           
  Lines        1562     1562           
  Branches      143      143           
=======================================
  Hits         1337     1337           
  Misses        180      180           
  Partials       45       45