Dex fails to parse oidc relation's client_id when container is replanned

[natalian98]

Concerns PR #62
When using container.replan() in a sidecar charm, oidc relation gets broken without being explicitly noted in juju logs.
Bundle deployed on microk8s 1.21/stable with dns storage rbac ingress metallb:10.64.140.43-10.64.140.49 enabled:

bundle: kubernetes
name: kubeflow
applications:
  dex-auth:
    charm: "/home/ubuntu/dex-auth-operator/dex-auth_ubuntu-20.04-amd64.charm"
    resources:
      oci-image: "dexidp/dex:v2.31.2"
    scale: 1
    trust: true
  istio-ingressgateway:          { charm: istio-gateway,           channel: 1.5/stable, scale: 1, trust: true}
  istio-pilot:                   { charm: istio-pilot,             channel: 1.5/stable, scale: 1, options: { default-gateway: "kubeflow-gateway" } }
  kubeflow-dashboard:            { charm: kubeflow-dashboard,      channel: latest/edge, scale: 1 }
  kubeflow-profiles:             { charm: kubeflow-profiles,       channel: latest/edge, scale: 1 }
  oidc-gatekeeper:               { charm: oidc-gatekeeper,         channel: latest/stable, scale: 1 }
relations:
- [dex-auth:oidc-client, oidc-gatekeeper:oidc-client]
- [istio-pilot:ingress, dex-auth:ingress]
- [istio-pilot:ingress, kubeflow-dashboard:ingress]
- [istio-pilot:ingress, oidc-gatekeeper:ingress]
- [istio-pilot:ingress-auth, oidc-gatekeeper:ingress-auth]
- [istio-pilot:istio-pilot, istio-ingressgateway:istio-pilot]
- [kubeflow-profiles, kubeflow-dashboard]

Charms get active, but the logon page shows info about invalid oidc client.
The following can be observed in dex container logs:

$ kubectl logs dex-auth-0 -c dex -n kubeflow
[...]
2022-06-24T13:50:14.025Z [dex] time="2022-06-24T13:50:14Z" level=error msg="Failed to parse authorization request: Invalid client_id (\"authservice-oidc\")."

However, when you inspect the config file to which that relation data is sent, the client id seems to be correct:

$ kubectl exec -it dex-auth-0 -c dex -n kubeflow -- cat /etc/dex/config.docker.yaml
connectors: null
enablePasswordDB: true
issuer: http://10.64.140.43.nip.io/dex
logger:
  format: text
  level: debug
oauth2:
  skipApprovalScreen: true
staticClients:
- id: authservice-oidc
  name: Ambassador Auth OIDC
  redirectURIs:
  - /authservice/oidc/callback
  secret: VAVFN2LPMVAUY577DULT42HXYR2SNL
staticPasswords:
- email: admin
  hash: $2b$12$vXZg1qLLMAqIXiXSYKSN5.ohyeQTbuLhCWvB.8wo9aML3CuR6zPi6
  userID: fdef551a-7377-4445-b070-5f2fdaa0b48b
  username: admin
storage:
  config:
    inCluster: true
  type: kubernetes
web:
  http: 0.0.0.0:5556

This is similar to issue #31.
This issue is not observed when container.restart() is used instead.