Add packaging test in pipeline

User Story

As a maintainer, I want a test in the pipeline that ensures that the extension can be packaged so I don't have to add fixes when I want to publish a new version.

Notes

Traceability

• Related to: #
• T-Reqs ID:
• Requirement label:

Acceptance criteria

• Remove publishing as pre-release
• Publishing job shall use packaged file from pipeline, not package it again
• Job shall run with same criteria as treqs-ts
• Job shall expose artifact, but expire within 7 days
• Update README images to be compatible