I removed the TARGETPLATFORM check in Alpine and Debian images as we're not publishing any arm/v7 image of this kind.
The Debian 21 "preview" Dockerfile has been modified to not use jlink as it's published only for arm/v7 architecture to avoid jlink's "jmods: Value too large for defined data type" error.
Testing done
Local builds + CI
### Submitter checklist
- [x] Make sure you are opening from a **topic/feature/bugfix branch** (right side) and not your main branch!
- [x] Ensure that the pull request title represents the desired changelog entry
- [x] Please describe what you did
- [x] Link to relevant issues in GitHub or Jira
- [x] Link to relevant pull requests, esp. upstream and downstream changes
- [x] Ensure you have provided tests - that demonstrates feature works or fixes the issue
This PR integrates jlink improvement from https://github.com/jenkinsci/docker/pull/1857.
Notes:
Testing done
Local builds + CI