## What this PR does
When deleting a Kubernetes, some resources may linger post deletion
because of a race to remove HelmReleases deployed inside the tenant
cluster and the removal of the cluster and its controlplane itself. This
patch modifies the existing pre-delete hook to remove those helmreleases
instead of simply suspending them. Similarly, datavolumes may also
remain. These are now delete with a post-delete hook.
### Release note
```release-note
[kubernetes] Use Helm hooks to clean up HelmReleases deployed in tenant
clusters and DataVolumes backing the tenant clusters' PVCs when deleting
a tenant Kubernetes.
```
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Chores**
* Added an automated post-delete cleanup job to remove persistent data
volumes scoped to the release namespace when a release is deleted.
* Updated Helm release teardown to actively delete lingering release
resources (rather than only suspending them) for cleaner uninstall
behavior.
* Broadened lifecycle hooks to run on successful completions and
expanded teardown permissions to list and delete related release
artifacts, including gateway CRDs.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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