Three new metrics are added for checking node and node pool status

## Feature Three new metrics are added for checking node and node pool status: * `kubernetes.io/node/status_condition`: The condition of a node from the node status condition field. The `Ready` field has `Unknown` status if the node controller has not heard from the node in the last `node-monitor-grace-period` period. This metric is available for clusters with GKE version 1.32.1-gke.1260000 and later. * `kubernetes.io/node_pool/multi_host/available`: The multi-host NodePool availability. When _all_ the nodes in the node pool are available, the value is `True`. If any of the nodes in the node pool are unavailable, the value is `False`. This metric is available for Multi-host TPU node pools only. * `kubernetes.io/node_pool/status`: The current status of the node pool from the `NodePool` instance. Status updates happen after GKE API operations complete. This metric is available for Multi-host TPU node pools only.