Automatic merge from submit-queue (batch tested with PRs 50302, 50573, 50500, 50633, 50617)

Fix kubernetes-worker charm hook failure when applying labels

**What this PR does / why we need it**:

This fixes a failure that can occur in the kubernetes-worker charm when trying to apply node labels.

The failure is rare, and can occur in two situations that I've seen:
1. kube-apiserver is not up yet
2. kubelet has not registered itself as a node yet

Rather than give up right away, let's give the services a minute to come up.

**Release note**:

```release-note
Fix kubernetes-worker charm hook failure when applying labels
```