Update the MSIXBundle-VPack pipeline to create VPack for both LTS and Stable channel packages by daxian-dbw · Pull Request #27384 · PowerShell/PowerShell

… Stable channel packages

- Remove signed individual files from the output directory, to avoid the CredSign error that came from nowhere in the pipeline run on 4/23/26
- Update the pipeline to handle creating VPack packages for both the LTS and Stable channels
   - Move the pack-sign-create-vpack job to a template
   - Create 2 explicit jobs for creating LTS vpack and stable vpack respectively. The job is guarded by a condition to test if we are supposed to publish to the corresponding channel. The job is skipped if we are not publishing to that channel.
   - Use different VPack package names for those 2 branches -- `PowerShell7-LTS.Store.app` and `PowerShell7-Stable.Store.app`