Manually setting shard in cluster by patching secret with incorrect value leads to cluster to be unmanaged

[akram]

• I've searched in the docs and FAQ for my answer: https://bit.ly/argocd-faq.
• I've included steps to reproduce the bug.
• I've pasted the output of argocd version.

Describe the bug

Manually setting shard in cluster by patching secret with incorrect value leads to cluster to be unmanaged.
If the manually set shard is greater than the number of replicas, then the cluster is assigned to a non existant shard and thus it is ignored by all the shards and it become unamaged de-facto.

To Reproduce

• Edit a cluster secret by setting: stringData: { shard: 25 }
• Have an application-controller with a number of replicas lower than 25.

Expected behavior
The application controller should issue a warning and assign the cluster to a default placement as if the manually set shard was not set.

Screenshots

Version

argocd: v2.6.7+5bcd846
  BuildDate: 2023-03-23T15:24:49Z
  GitCommit: 5bcd846fa16e4b19d8f477de7da50ec0aef320e5
  GitTreeState: clean
  GoVersion: go1.18.10
  Compiler: gc
  Platform: linux/amd64```

**Logs**

Paste any relevant application logs here.