fix(monitoring): scope Azure Monitor SecretProviderClass directory source

Copilot flagged that the new git directory source over
k8s/infra-manifest/monitoring would also try to apply the Helm
values files (helm-values.yaml, loki-values.yaml, alloy-values.yaml)
as raw manifests, risking sync errors. Scope it to only
secret-provider-class.yaml via directory.include.

Author: hakan-persson

k8s/argocd/infra-apps/monitoring.yaml

@@ -18,6 +18,8 @@ spec:
     - repoURL: https://github.com/Scouterna/j26-infra.git
       targetRevision: main
       path: k8s/infra-manifest/monitoring
+      directory:
+        include: "{secret-provider-class.yaml}"
     - repoURL: ghcr.io/prometheus-community/charts
       chart: kube-prometheus-stack
       targetRevision: "80.2.2"