feat(helm): allow set topologySpreadConstraints on singleBinary

[mvink-guida]

What this PR does / why we need it:
Allow balance singleBinary replicas when using 3 replicas and objectStorage over just two nodes or zones.
With topologySpreadConstraints you can accomplish affinity just over two topologyKeys and so allow cluster autoscaler to scale back to two nodes/zones, in our case zoneC(or the 3rd node) should stay optional as fallback. With podAntiAffinity you can not accomplish this.

singleBinary:
  affinity: null
  topologySpreadConstraints:
    - maxSkew: 2
      minDomains: 2
      topologyKey: topology.kubernetes.io/zone
      whenUnsatisfiable: DoNotSchedule
      labelSelector:
        matchLabels:
          app.kubernetes.io/component: single-binary
          app.kubernetes.io/instance: loki
          app.kubernetes.io/name: loki

Which issue(s) this PR fixes:
Fixes #10205

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
• 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

[CLAassistant]

All committers have signed the CLA.

[jkroepke]

Hi, please run make helm-docs and add a CHANGELOG note