Add test to confirm the general purpose bit flag is unset when no encoding is specified in ZipArchive

[carlossanlop]

Follow up of issue #87658

Continuation of PR #87883

Tagging subscribers to this area: @dotnet/area-system-io-compression
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Follow up of issue #87658

Author:	carlossanlop
Assignees:	carlossanlop
Labels:	area-System.IO.Compression
Milestone:	8.0.0