game: send the client brand once per connection, as the vanilla client does

[u9g]

On 1.20.2+ the client brand goes out twice.

node-minecraft-protocol already sends it correctly, on the first entry into the configuration state, which is where the vanilla client sends it (ClientHandshakePacketListenerImpl: login_acknowledged → BrandPayload → ClientInformation). game.js then writes it again on every login packet, so a fresh connection sends two, and every Velocity backend transfer — which re-enters configuration and sends a second login — sends another. Vanilla sends none of those: BrandPayload appears only in the handshake listener, never in ClientPacketListener, and re-entering configuration from play sends nothing.

Before the configuration state existed the client did send the brand on joining the world (1.19.4 ClientPacketListener.handleLogin), so the write stays for those versions — the same shape settings.js already uses for Client Information:

bot._client.on('login', () => {
  if (!bot.supportFeature('hasConfigurationState')) setSettings({})
})

Measured against a live 26.1 server (JartexNetwork, Velocity), tracing every outgoing packet from before the socket opened.

Fresh connection, before:

> login_acknowledged [login]
> custom_payload [configuration] vanilla
> settings [configuration]
> select_known_packs [configuration]
> finish_configuration [configuration]
< login
> custom_payload [play] vanilla        <- extra

After: the [play] one is gone, one brand total.

Backend transfer, before: < start_configuration … < login then > custom_payload [play] vanilla. After: no brand at all, and the transfer still completes.

npm run mocha_test: 763 passing / 73 pending / 4 failing, and unmodified master at the same commit gives 763 / 73 / 4 as well — the failures are the pre-existing flaky world switchWorld respawn, which times out on a different random subset of pre-1.20.2 versions on each run (mine: 1.10.2, 1.11.2, 1.18.2, 1.19.3; master's: 1.14.4, 1.15.2, 1.16.5, 1.19.2). Those are all versions where this change is a no-op.

[github-actions]

Tests more than 1.5x slower than master (durations are noisy, so this is informational):

   2950ms ->   14092ms  mineflayer_external 1.9.4v fishing

[u9g]

Needs PrismarineJS/node-minecraft-protocol#1522