Fix global_rules section to be conditionally included

Made the global_rules section conditional on logging being enabled.
Previously, when logging was disabled, global_rules was rendered as
an empty object (null), causing a lint error:
"Invalid input: expected record, received null at global_rules"

Now the entire global_rules section is only included when there are
actual rules to add.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

helm/api7ee-demo-k8s/templates/configmap-adc.yaml

@@ -126,10 +126,10 @@ data:
             key: {{ .apiKey }}
       {{- end }}
     {{- end }}
+{{- if .Values.api7.plugins.logging.enabled }}
 
     # Global Rules
     global_rules:
-      {{- if .Values.api7.plugins.logging.enabled }}
       request-logging:
         plugins:
           http-logger: