chore(server): switch to prometheus (#12352)

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

## Summary by CodeRabbit

- **New Features**
  - Added platform-specific monitoring integration for Google Cloud Platform (GCP) in multiple services, enabling automated pod monitoring for deployments on GCP.

- **Chores**
  - Removed an unused dependency related to Google Cloud monitoring from the backend server package.

- **Refactor**
  - Updated internal monitoring implementation by removing a previously used metric reader method for GCP integration.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/package.json

@@ -36,7 +36,6 @@
     "@aws-sdk/client-s3": "^3.779.0",
     "@aws-sdk/s3-request-presigner": "^3.779.0",
     "@fal-ai/serverless-client": "^0.15.0",
-    "@google-cloud/opentelemetry-cloud-monitoring-exporter": "^0.20.0",
     "@google-cloud/opentelemetry-cloud-trace-exporter": "^2.4.1",
     "@google-cloud/opentelemetry-resource-util": "^2.4.0",
     "@nestjs-cls/transactional": "^2.6.1",