fix(cilium): wire cilium_enable_prometheus to Helm values template (#13142)

The cilium_enable_prometheus variable was defined in defaults and
documented in sample inventory but never mapped to the Helm values
template, making it a no-op. Add the prometheus.enabled field to
values.yaml.j2 so that setting cilium_enable_prometheus: true
correctly enables Prometheus metrics on the Cilium agent.

Signed-off-by: Kay Yan <kay.yan@daocloud.io>

.github/workflows/upgrade-patch-versions.yml

@@ -29,7 +29,7 @@ jobs:
           ~/.cache/pre-commit
     - run: pre-commit run --all-files propagate-ansible-variables
       continue-on-error: true
-    - uses: peter-evans/create-pull-request@c0f553fe549906ede9cf27b5156039d195d2ece0
+    - uses: peter-evans/create-pull-request@5f6978faf089d4d20b00c7766989d076bb2fc7f1
       with:
         commit-message: Patch versions updates
         title: Patch versions updates - ${{ inputs.branch }}

roles/network_plugin/cilium/templates/values.yaml.j2

@@ -177,6 +177,9 @@ hostFirewall:
 
 policyAuditMode: {{ cilium_policy_audit_mode | to_json }}
 
+prometheus:
+  enabled: {{ cilium_enable_prometheus | to_json }}
+
 certgen:
   image:
     repository: {{ cilium_hubble_certgen_image_repo }}