azure: fix BYOCNI install with Cilium >= 1.12

[nbusseneau]

We introduced support for BYOCNI with the aks-byocni datapath mode in 2e1d3b5, and properly guarded the previously existing Service Principal creation to only be done when using Azure IPAM (azure datapath mode), however we forgot to do the same for the newly-introduced AKS secrets in the Cilium 1.12 Helm chart.

This went undetected during the initial implementation as the Helm chart used was either the stable 1.11.5 or the development version 1.11.90 when directly using the Helm chart from upstream master branch, in both cases skipping the existing 1.12 check for creating AKS secrets.

Now, after the 1.12 branch was properly created and the development version bumped to 1.12.90, this does not work anymore, and explains why the AKS BYOCNI CI in upstream was initially working but then started to fail after the version bump.

[nbusseneau]

Before fix (install/kubernetes/cilium == Helm chart from upstream master branch, ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4 == current upstream master branch):

~/.local/bin/cilium install \
  --chart-directory=install/kubernetes/cilium \
  --agent-image=quay.io/cilium/cilium-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4 \
  --operator-image=quay.io/cilium/operator-generic-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4 \
  --version=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4 \
  --azure-resource-group nicolas-test2 \
  --wait=false \
  --rollback=false \
  --config monitor-aggregation=none \
  --helm-set=debug.enabled=true
🔮 Auto-detected Kubernetes kind: AKS
✨ Running "AKS" validation checks
✅ Detected az binary
ℹ️  Using Cilium version 1.12.90
🔮 Auto-detected cluster name: nicolas-test2
✅ Derived Azure subscription ID 22716d91-fb67-4a07-ac5f-d36ea49d6167 from subscription cilium-dev
✅ Detected Azure AKS cluster in BYOCNI mode (no CNI plugin pre-installed)
🔮 Auto-detected datapath mode: aks-byocni
ℹ️  helm template --namespace kube-system cilium "install/kubernetes/cilium" --version 1.12.90 --set azure.resourceGroup=nicolas-test2,cluster.id=0,cluster.name=nicolas-test2,clustermesh.apiserver.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,clustermesh.apiserver.image.useDigest=false,debug.enabled=true,encryption.nodeEncryption=false,extraConfig.monitor-aggregation=none,hubble.relay.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,hubble.relay.image.useDigest=false,image.override=quay.io/cilium/cilium-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,image.useDigest=false,ipam.mode=cluster-pool,kubeProxyReplacement=disabled,nodeinit.enabled=true,operator.image.override=quay.io/cilium/operator-generic-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,operator.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,operator.image.useDigest=false,operator.replicas=1,preflight.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,preflight.image.useDigest=false,serviceAccounts.cilium.name=cilium,serviceAccounts.operator.name=cilium-operator,tunnel=vxlan
ℹ️  Storing helm values file in kube-system/cilium-cli-helm-values Secret
🔑 Generated AKS secret cilium-azure
ℹ️  Rollback disabled with '--rollback=false', leaving installed resources behind

Error: Unable to install Cilium: unable to create AKS secret kube-system/cilium-azure: Secret "" is invalid: metadata.name: Required value: name or generateName is required

After fix:

~/.local/bin/cilium install \   
  --chart-directory=install/kubernetes/cilium \
  --agent-image=quay.io/cilium/cilium-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4 \
  --operator-image=quay.io/cilium/operator-generic-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4 \
  --version=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4 \
  --azure-resource-group nicolas-test2 \
  --wait=false \
  --rollback=false \
  --config monitor-aggregation=none \
  --helm-set=debug.enabled=true
🔮 Auto-detected Kubernetes kind: AKS
✨ Running "AKS" validation checks
✅ Detected az binary
ℹ️  Using Cilium version 1.12.90
🔮 Auto-detected cluster name: nicolas-test2
✅ Derived Azure subscription ID 22716d91-fb67-4a07-ac5f-d36ea49d6167 from subscription cilium-dev
✅ Detected Azure AKS cluster in BYOCNI mode (no CNI plugin pre-installed)
🔮 Auto-detected datapath mode: aks-byocni
ℹ️  helm template --namespace kube-system cilium "install/kubernetes/cilium" --version 1.12.90 --set azure.resourceGroup=nicolas-test2,cluster.id=0,cluster.name=nicolas-test2,clustermesh.apiserver.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,clustermesh.apiserver.image.useDigest=false,debug.enabled=true,encryption.nodeEncryption=false,extraConfig.monitor-aggregation=none,hubble.relay.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,hubble.relay.image.useDigest=false,image.override=quay.io/cilium/cilium-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,image.useDigest=false,ipam.mode=cluster-pool,kubeProxyReplacement=disabled,nodeinit.enabled=true,operator.image.override=quay.io/cilium/operator-generic-ci:ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,operator.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,operator.image.useDigest=false,operator.replicas=1,preflight.image.tag=ae43e20c2defb23b2c4c16efdec9f26aa8aec1c4,preflight.image.useDigest=false,serviceAccounts.cilium.name=cilium,serviceAccounts.operator.name=cilium-operator,tunnel=vxlan
ℹ️  Storing helm values file in kube-system/cilium-cli-helm-values Secret
🔑 Created CA in secret cilium-ca
🔑 Generating certificates for Hubble...
🚀 Creating Service accounts...
🚀 Creating Cluster roles...
🚀 Creating ConfigMap for Cilium version 1.12.90...
ℹ️ Manual overwrite in ConfigMap: monitor-aggregation=none
🚀 Creating AKS Node Init DaemonSet...
🚀 Creating Agent DaemonSet...
🚀 Creating Operator Deployment...
⌛ Waiting for Cilium to be installed and ready...
✅ Cilium was successfully installed! Run 'cilium status' to view installation health

[nbusseneau]

Fixed typos in git commit message, no changes otherwise, marking as ready-to-merge.