fix(argo-cd): Add required label for CLI on redis-ha-haproxy pod

[mkilchhofer]

Fixes #2621

Details:

$ argocd admin cluster stats -h
Prints information cluster statistics and inferred shard number

Usage:
  argocd admin cluster stats [flags]

Examples:

#Display stats and shards for clusters
argocd admin cluster stats

#Display Cluster Statistics for a Specific Shard
argocd admin cluster stats --shard=1

#In a multi-cluster environment to print stats for a specific cluster say(target-cluster)
argocd admin cluster stats target-cluster

Flags:
      -- ...

Global Flags:
      ...
      --redis-haproxy-name string       Name of the Redis HA Proxy; set this or the ARGOCD_REDIS_HAPROXY_NAME environment variable when the HA Proxy's name label differs from the default, for example when installing via the Helm chart (default "argocd-redis-ha-haproxy")
      --redis-name string               Name of the Redis deployment; set this or the ARGOCD_REDIS_NAME environment variable when the Redis's name label differs from the default, for example when installing via the Helm chart (default "argocd-redis")
      ...

Checklist:

• I have bumped the chart version according to versioning
• I have updated the documentation according to documentation
• I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• Any new values are backwards compatible and/or have sensible default.
• I have signed off all my commits as required by DCO.
• My build is green (troubleshooting builds).