Fix GitHub release and add stage dependency for Universal package release

[adityapatwardhan]

PR Summary

This pull request makes several updates to the .pipelines/DSC-Official.yml pipeline configuration, primarily focused on improving artifact handling and changelog management during the release process. The changes simplify the copying of artifacts, adjust how changelogs are managed, and enhance the release logic to better distinguish between pre-release and stable release workflows.

Artifact and changelog handling improvements:

• Removed the explicit copying and existence check for the CHANGELOG.md file during artifact preparation, simplifying the release artifact process.
• Updated artifact discovery to exclude .MD files, ensuring only relevant package files are included in the release.
• Removed the creation of a dedicated ChangeLogDirectory and the copying of CHANGELOG.md to this directory, streamlining changelog management.

Release workflow enhancements:

• Added logic to set the ChangeLogCompareToRelease variable based on whether the release is a pre-release or stable release, allowing for more accurate changelog generation.
• Updated the GitHub release task to use the new changeLogCompareToRelease variable instead of a static changelog file path, and ensured .msixbundle files are included in release assets. Also adjusted stage dependencies to ensure proper sequencing.

PR Context