LT-22425: Fix testSetTextEmpty for Release builds

[papeh]

Summary

Sleep 1ms at the beginning of the MockTextStoreACPSink ctor to prevent an "unknown exception" in the test for VwTextStore.SetTextEmpty in Release builds (Debug builds are fine).

Also

• Add a -SkipManagedTests switch to build.ps1
• Split tests into a separate execution step for installer builds for consistency with CI builds and more manageable log sizes

Notes for reviewers (optional)

Another option is to cout << "";, which also spends enough time doing effectively nothing to cause the test to pass, and doesn't require two extra #includes, but sleeping rather than couting when the goal is to kill time feels more principled to me.

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This change is 

[github-actions]

NUnit Tests

    1 files  ±0      1 suites  ±0   7m 11s ⏱️ + 1m 5s
4 103 tests ±0  4 032 ✅ ±0  71 💤 ±0  0 ❌ ±0 
4 112 runs  ±0  4 041 ✅ ±0  71 💤 ±0  0 ❌ ±0 

Results for commit b204d9b. ± Comparison against base commit 59c00b0.

♻️ This comment has been updated with latest results.

[papeh]

This works, and the logs look nice in the GHA web interface, but the downloaded build.log is missing the native logs. https://github.com/sillsdev/FieldWorks/actions/runs/24748859269 tests a tweak that I hope will fix this.

[github-actions]

⚠️ Commit Message Format Issues ⚠️
commit b204d9b50b:
3: B5 Body message is too short (16<20): "not just stdout."

[mark-sil]

@mark-sil reviewed 4 files and all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on papeh).