PR Summary

This is a follow-up on #26796

The updatable help tests are only failing with the PackageManagement module in Linux CI on release/v7.6, release/v7.5, and release/v7.4 branches. And it's the "Tag: Feature" tests are failing (see an example CI at https://github.com/PowerShell/PowerShell/actions/runs/22045492577/job/63693733570#step:3:3280).

The PR #26796 marked pending on the wrong tests and thus the failure still happens in release/v7.5 branch.
This change updates the test to only mark the test targeting PackageManagement module pending on Linux. Here is a successful CI run with the fix: https://github.com/PowerShell/PowerShell/actions/runs/22113437487/job/63915672423#step:3:3285

  Describing Validate Update-Help from the Web for all PowerShell modules.
+?++++?++++?

  Describing Validate Update-Help from the Web for all PowerShell modules for user scope.
+?++++?++++?

  Describing Validate Update-Help -SourcePath for all PowerShell modules.
+?++++?++++?

  Describing Validate Update-Help -SourcePath for all PowerShell modules for user scope.
+?++++?++++?

NOTE this change is already available in the release/v7.5 branch via this PR: #26837

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• 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
  • OR
  • Experimental feature(s) needed
    • Experimental feature name(s):
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed