Ingest sidekiq_exporter logs into ELK

For production readiness, we should ingest logs emitted by GME into our ELK stack for better visibility into this system.

These logs are currently disabled by default for sidekiq_exporter and our GitLab chart does not allow admins to override this setting.

We should patch the Helm chart to support the log_enabled setting for Sidekiq metrics, let it default to false, and update SaaS overrides to set it to true.

We don't need to do this for web_exporter because it is hard-coded to always emit logs.