Charm version is obsolete

## Summary
Outdated charm revisions with incompatible container images are causing systematic test failures. These revisions should be deprecated or removed from stable channels.

## Example Case: zookeeper-k8s revision 21
- **Channel**: 3/stable
- **Failure Rate**: 100% (last 10 test executions)
- **Error**: `cannot start service: fork/exec /bin/zkServer.sh: no such file or directory`
- **Root Cause**: Revision uses obsolete container image where expected binaries don't exist
- **Test Execution**: https://test-observer-api.canonical.com/v1/test-executions/298189
- **Fixed In**: Revision 73+ (PR canonical/kafka-k8s-operator#73, Feb 2024)

Start with the zookeeper-k8s revision 21 failure in test execution 298189 and inspect how stable-channel charm revisions are tracked in this repository. Compare the obsolete revision with revision 73+ from canonical/kafka-k8s-operator#73, then verify that incompatible revisions are deprecated or removed from stable channels and no longer produce these test failures.

Written by the indexing model from the issue text.