Update the PowerShell 7.4 SDK version

[andystaples]

Update PowerShell 7.4 to SDK 7.4.0-preview.6

resolves #1009

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

[Francisco-Gamino]

LGTM.

Please add in the commit history that we updated the language worker to .Net 8 '100-rc.2.23502.2' as well.