[JUJU-998] Fix/lp1968643

[ycliuhw]

This PR allows juju_start_unit, juju_stop_unit and juju_unit_status returning proper not supported errors on CAAS controller, operator and sidecar charm container.

Checklist

• Requires a pylibjuju change
• Added integration tests for the PR
• Added or updated doc.go related to packages changed
• Comments answer the question of why design decisions were made

QA steps

$ juju bootstrap microk8s k1

$ juju add-model t1

$ juju deploy hello-kubecon

$ juju deploy minio

$ mkubectl exec -ncontroller-k1 pod/controller-0 -c api-server  -it -- bash --login
root@controller-0:/var/lib/juju# juju_start_unit hello-kubecon/0
error: start units for {[hello-kubecon/0]} not supported
root@controller-0:/var/lib/juju# juju_stop_unit hello-kubecon/0
error: stop units for {[hello-kubecon/0]} not supported
root@controller-0:/var/lib/juju# juju_unit_status hello-kubecon/0
error: units status not supported

$ mkubectl exec -nt1 pod/hello-kubecon-0   -it -- bash --login
Defaulted container "charm" out of: charm, gosherve, charm-init (init)
root@hello-kubecon-0:/var/lib/juju# juju_start_unit hello-kubecon/0
error: start units for {[hello-kubecon/0]} not supported
root@hello-kubecon-0:/var/lib/juju# juju_stop_unit hello-kubecon/0
error: stop units for {[hello-kubecon/0]} not supported
root@hello-kubecon-0:/var/lib/juju# juju_unit_status hello-kubecon/0
error: units status not supported

$ mkubectl exec -nt1 pod/minio-operator-0   -it -- bash --login
root@minio-operator-0:/var/lib/juju# juju_start_unit minio/0
error: start units for {[minio/0]} not supported
root@minio-operator-0:/var/lib/juju# juju_stop_unit minio/0
error: stop units for {[minio/0]} not supported
root@minio-operator-0:/var/lib/juju# juju_unit_status minio/0
error: units status not supported

Documentation changes

No

Bug reference

https://bugs.launchpad.net/juju/+bug/1968643

[wallyworld]

Thank you

[ycliuhw]

$$merge$$