KCP: Consider reconciling on Pod events

We recently changed KCP to use a cached client to retrieve the Pods we care about.

This means we already have informers for Pods of workload clusters.

I'm wondering if we should also trigger reconciles if these Pods change (similar to how we watch on Node events in the Machine controller).

Pro

• we can instantly react to Pod changes instead of using requeue after

Con

• we get probably more reconciles
  • This can be mitigated by only letting the update events through that we care about or by rate-limiting. This might even lead to less reconciles when we get rid of the requeues we have because we don't watch on Pod events (https://github.com/kubernetes-sigs/cluster-api/blob/d9341254c25ca578f9c82d5cf69f58c1ffc59a9b/controlplane/kubeadm/internal/controllers/controller.go#L253)