add Label field to user_trade

[kevenli]

Deribit Doc missed a "label" field on user.trade.xxx event data. The "label" contains corresponding label parameter of the buy/sell request.

Since user.trades.xxx event is earlier than user.orders.xxx, handling by label is more efficient.

Here is the log to show that the field exists.

2024/10/10 01:53:44 sendOrder, &{{bc100da0-b9f3-4991-9679-a7d189986922 bc100da0-b9f3-4991-9679-a7d189986922  0xc00014eb80 1 1 1 1 10 0 1 0001-01-01 00:00:00 +0000 UTC 0 0 []} 0xc0001247e0  {0 0}  }
2024/10/10 01:53:44 sendOrder params: {BTC-PERPETUAL 10 market bc100da0-b9f3-4991-9679-a7d189986922 0 good_til_cancelled <nil> false false 0  }
2024/10/10 01:53:44 Channel: user.trades.any.any.raw [{"liquidity":"T","risk_reducing":false,"order_type":"market","trade_id":"191715010","fee_currency":"BTC","contracts":1.0,"reduce_only":false,"self_trade":false,"post_only":false,"mmp":false,"fee":8e-8,"tick_direction":0,"matching_id":null,"order_id":"28923304722","mark_price":60763.53,"api":true,"trade_seq":113665972,"instrument_name":"BTC-PERPETUAL","profit_loss":0.0,"index_price":60721.31,"direction":"buy","amount":10.0,"price":60810.0,"state":"filled","timestamp":1728525224281,"label":"bc100da0-b9f3-4991-9679-a7d189986922"}]