fix kad quorum

[turuslan]

• insufficient quorum is not an error

  polkadot-sdk/substrate/client/network/src/discovery.rs:
       96: // The minimum number of peers we expect an answer before we terminate the request.
       97: const GET_RECORD_REDUNDANCY_FACTOR: u32 = 4;
      889:     Ok(GetRecordOk::FoundRecord(r)) => {
      899:       // Let's directly finish the query if we are above 4.
      905:       if stats.num_successes() > GET_RECORD_REDUNDANCY_FACTOR {
      908:         query.finish();
      917:       DiscoveryOut::ValueFound(r, stats.duration().unwrap_or_default())
      919:     Ok(GetRecordOk::FinishedWithNoAdditionalRecord {