Reuse integration test project data in RootSite tests

[johnml1135]

Summary

• reuse a fixed integration_test_data project name in RealDataTestsBase instead of generating a new RealDataTest_<guid> project for each run
• delete the actual created project directory before setup and after teardown so repeated test runs do not accumulate dummy projects
• keep the change scoped to the RootSite real-data test base used by the render verification/timing fixtures

Validation

• ./test.ps1 -TestProject RootSiteTests -TestFilter "FullyQualifiedName~RenderVerifyTests" -NoBuild
• CI: Whitespace check
• CI: Commit messages

---

This change is 

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Reworks RootSite real-data test setup/teardown to reuse a fixed integration test project name and clean up the created project directory between runs, avoiding accumulation of dummy projects.

Changes:

• Use a constant project name (integration_test_data) instead of a per-run GUID project name.
• Delete the project directory before setup and after teardown.
• Track the created project directory from CreateNewLangProj and reuse it for cleanup.

[github-actions]

NUnit Tests

    1 files  ±0      1 suites  ±0   12m 5s ⏱️ + 1m 49s
4 205 tests ±0  4 134 ✅ ±0  71 💤 ±0  0 ❌ ±0 
4 214 runs  ±0  4 143 ✅ ±0  71 💤 ±0  0 ❌ ±0 

Results for commit 9348219. ± Comparison against base commit ad3b499.

♻️ This comment has been updated with latest results.