fix: return correct message about unsupported protocol

[weisdd]

Description

There's a cosmetic bug in getGrafanaAdminUrl - if unsupported protocol is chosen through config.server.protocol, the operator would always complain about http instead of actual protocol: server protocol http is not supported, please use either http or https.

The PR fixes that.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• This change requires a documentation update
• I have added tests that prove my fix is effective or that my feature works
• I have added a test case that will be used to verify my changes
• Verified independently on a cluster by reviewer

Verification steps

Deploy grafana with the following config:

apiVersion: integreatly.org/v1alpha1
kind: Grafana
metadata:
  name: example-grafana
spec:
  client:
    preferService: true
  config:
    server:
      protocol: unknown-protocol

You should see a reference to unknown-protocol in the error message:
grafana-operator-846d554b57-vvxgs grafana-operator 2022-07-20T16:28:21.238Z DEBUG controller-runtime.manager.events Warning {"object": {"kind":"Grafana","namespace":"monitoring","name":"example-grafana","uid":"f218c504-fd0a-4fc2-8e6f-5519f369c97c","apiVersion":"integreatly.org/v1alpha1","resourceVersion":"503482"}, "reason": "ProcessingError", "message": "server protocol unknown-protocol is not supported, please use either http or https"}

[weisdd]

@HubertStefanski since gofumpt automatically made the same code style changes as in the branch that got merged to master, there was a merge conflict. I've just rebased the branch to mitigate that, everything is fine now.

[NissesSenap]

@weisdd why not use a enum In the CRD to solve this as well? We can of course still update code as well.

[weisdd]

@NissesSenap it's actually already covered by the enum that was introduced in the branch with probes refactoring. If we are to assume that all people keep their CRDs updated, then we can remove this part of the code altogether. If we rather decide to keep some sort of additional config validation through the code for v4.x, then we should better leave it for now and maybe deprecate in v5. WDYT? :)

[NissesSenap]

Sounds very reasonable. Always good to print out extra info.