Improve the repos/pipelines used to test the abi-checker job

Background

• tests/zlib This repo is used to test the abi-checker job, but it's broken since we use the obs-capture job because .dsc files are not captured as a job artifact whereas they are required.
• tests/zlib_broken: This repo is used to test the abi-checker job, the pipeline seems to be broken since the rebase on Bookworm.

Reproducibility

How often the issue is hit when repeating the steps to reproduce and changing nothing?

Put the ✅ in the most appropriate entry:

1. ✅ always
2. often, but not always
3. rarely

Impact of bug

It's not possible to test if an update introduces an ABI breakage.

Outcomes

TBD

Management data

This section is for management only, it should be the last one in the description.

/cc @andrunko @em @Balasubramanian @sudarshan @wlozano

Phabricator link: https://phabricator.apertis.org/T10681