text: Title: [Core] Stale ray_cluster_<state>_nodes metrics
  Body: ### What happened + What you expected to happen
  
  I am observing stale values for `ray_cluster_active_nodes` and `ray_cluster_pending_nodes` metrics.
  
  Example:
  
  Dashboard shows this (accurate):
  
  ![Image](https://github.com/user-attachments/assets/3b397510-f012-4eb4-b859-8e6924500e82)
  
  However, `http://10.212.14.97:8080/metrics` shows this (inaccurate):
  
  ```
  # HELP ray_cluster_active_nodes Active nodes on the cluster
  # TYPE ray_cluster_active_nodes gauge
  ray_cluster_active_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="headgroup"} 1.0
  ray_cluster_active_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker2"} 1.0
  ray_cluster_active_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker4"} 1.0
  ray_cluster_active_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker8"} 6.0
  ray_cluster_active_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker16"} 3.0
  # HELP ray_cluster_pending_nodes Pending nodes on the cluster
  # TYPE ray_cluster_pending_nodes gauge
  ray_cluster_pending_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker2"} 1.0
  ray_cluster_pending_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker4"} 1.0
  ray_cluster_pending_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker8"} 3.0
  ray_cluster_pending_nodes{SessionName="session_2025-02-12_19-51-59_037643_1",Version="2.41.0",node_type="worker16"} 1.0
  ```
   
  
  ### Versions / Dependencies
  
  Ray version 2.41.0
  KubeRay version 1.2.2
  
  ### Reproduction script
  
  I've reproduced this multiple times in the context of KubeRay:
  
  - I restart the head pod and the metrics for worker nodes accurately reset to 0
  - I run some jobs, allowing the cluster to scale up and back down to zero worker nodes
  - the metrics for worker nodes are now inaccurate (non-zero)
  
  ### Issue Severity
  
  Low: It annoys or frustrates me.