Remove the `pretty` key from JSON logging

[OisinKyne]

🎯 Problem to be solved

If you turn log-format to JSON, you get the full normal log line as a key in the JSON, along with the JSON-ified value. This doubles the length of the log for little gain

🛠️ Proposed solution

Drop the pretty key from JSON logging

Example:

{"level":"warn","ts":"2025-08-22T06:52:31.762796658Z","caller":"peerinfo/peerinfo.go:255","msg":"Mismatching peer builder API status","peer":"selfish-box","peer_builder_api_enabled":true,"builder_api_enabled":false,"topic":"peerinfo","pretty":"WARN peerinfo   Mismatching peer builder API status      {\"peer\": \"selfish-box\", \"peer_builder_api_enabled\": true, \"builder_api_enabled\": false}\n"}

[KaloyanTanev]

I have to double check how the logs are ingested in our Loki first, not to break anything with the queries there.

[jakubgs]

It's not that it just doubles the size of the log, it also makes the JSON not parseable by jq:

 > echo '{"level":"warn","ts":"2025-08-22T06:52:31.762796658Z","caller":"peerinfo/peerinfo.go:255","msg":"Mismatching peer builder API status","peer":"selfish-box","peer_builder_api_enabled":true,"builder_api_enabled":false,"topic":"peerinfo","pretty":"WARN peerinfo   Mismatching peer builder API status      {\"peer\": \"selfish-box\", \"peer_builder_api_enabled\": true, \"builder_api_enabled\": false}\n"}' | jq .
jq: parse error: Invalid string: control characters from U+0000 through U+001F must be escaped at line 2, column 1

Works if I remove the pretty key:

 > echo '{"level":"warn","ts":"2025-08-22T06:52:31.762796658Z","caller":"peerinfo/peerinfo.go:255","msg":"Mismatching peer builder API status","peer":"selfish-box","peer_builder_api_enabled":true,"builder_api_enabled":false,"topic":"peerinfo"}' | jq .
{
  "level": "warn",
  "ts": "2025-08-22T06:52:31.762796658Z",
  "caller": "peerinfo/peerinfo.go:255",
  "msg": "Mismatching peer builder API status",
  "peer": "selfish-box",
  "peer_builder_api_enabled": true,
  "builder_api_enabled": false,
  "topic": "peerinfo"
}