PR Summary

Update PSVersionTable.Tests.ps1 so tag builds accept both valid GitCommitId forms:

• release tag builds that report only the semantic version, such as 7.6.2
• clean tag builds that report the git describe --long form, such as 7.6.2-0-g<sha>

PR Context

ProductVersion for a tag build can include SHA: <sha> even when the built GitCommitId is 7.6.2-0-g<sha>. The previous test treated the -0-g<sha> form as unexpected whenever ProductVersion did not include Commits:, which makes the test fail for clean builds from a release tag.

This keeps the exact check for normal commit builds, strips any +<source revision> suffix from the product-version SHA before comparing, and adds regression coverage for the zero-commit tag case.

Fixes #27503

PR Checklist

• PR has a meaningful title
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge. If this PR is a work in progress, please open this as a Draft Pull Request and mark it as Ready to Review when it is ready to merge.
• Breaking changes
  • None
• User-facing changes
  • Not Applicable
• Testing - New and feature
  • Added regression coverage for tag builds with zero commits

Tests

• Start-PSBootstrap -Scenario Dotnet
• Start-PSBuild -UseNuGetOrg -SkipExperimentalFeatureGeneration
• Start-PSPester -Path ./test/powershell/Host/PSVersionTable.Tests.ps1 -UseNuGetOrg -SkipTestToolBuild -ThrowOnFailure (16 passed)
• git diff --check