chore(jsonnet)!: convert read statefulset into deployment for loki-simple-scalable

[zalegrala]

What this PR does / why we need it:

Here we change the read statefulset into a deployment. The stateful nature of the read component has moved to the backend component, and so here we make the converstion and allow easier scalability of the read path.

BREAKING CHANGE Users will need to clean up the old statefulset, pvc and pv resources that were created for the read component. tk prune can help.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR