Automatic merge from submit-queue (batch tested with PRs 48439, 48440, 48394)

Fix kubernetes charms not restarting services after snap upgrades

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

This fixes a problem where the Kubernetes charms don't restart services after upgrading snaps. This can cause certain fixes not to be picked up (for example https://github.com/juju-solutions/release/pull/10)

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
Fixed kubernetes charms not restarting services after snap upgrades
```