AWS ALB healthcheck spam in logs

[sergiimk]

We have strategically exclude /system/health endpoint to prevent healthcheck spam in logs.

However for our gRPC (FlightSQL) interface our logs are full of healthcheck traffic:

{
  "log": {
    "spans": [
      {
        "name": "Grpc::request",
        "service": "AWS.ALB",
        "method": "healthcheck",
        "trace_id": "41ae8b4d31ed2fd9d3513d71e41de023",
        "otel.name": "AWS.ALB::healthcheck"
      }
    ],
    "level": "INFO",
    "fields": {
      "message": "GRPC request",
      "uri": "/AWS.ALB/healthcheck",
      "version": "HTTP/2.0",
      "headers": "{\"host\": \"AWSALB\", \"content-length\": \"5\", \"te\": \"trailers\", \"user-agent\": \"ELB-HealthChecker/2.0\", \"content-type\": \"application/grpc\", \"accept-encoding\": \"gzip, compressed\"}"
    },
    "line_number": 31,
    "threadName": "tokio-runtime-worker",
    "timestamp": "2025-03-28T21:43:29.686844Z",
    "target": "observability::tonic"
  },
  "time": "2025-03-28T21:43:29.687086023Z",
  "root_span": "Grpc::request"
}

This ticket is to filter out this spam from logs.

Note that /AWS.ALB/healthcheck service is not implemented by our gRPC interface and we currently have to use this workaround to make them succeed. We should consider either implmenting a generic healthcheck service in gRPC.