chore: use PodMonitoring in charts instead (#12571)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **Refactor**
  - Updated monitoring configuration to use a different resource type with simplified naming and label selectors for Kubernetes manifests.
- **Chores**
  - Removed Google Cloud Platform–specific monitoring configuration files from multiple components.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

.github/helm/affine/charts/sync/templates/monitoring.yaml

@@ -1,12 +0,0 @@
-{{- if eq .Values.global.deployment.platform "gcp" -}}
-apiVersion: monitoring.googleapis.com/v1
-kind: ClusterPodMonitoring
-metadata:
-  name: "{{ include "sync.fullname" . }}"
-spec:
-  selector:
-    {{- include "sync.selectorLabels" . | nindent 4 }}
-  endpoints:
-    - port: 9464
-      interval: 30s
-{{- end }}