Enhance Binance adapter to allow unauthed use of public endpoints

[stastnypremysl]

Feature Request

Problem Statement

When running

#!/usr/bin/env python3

import asyncio

from nautilus_trader.model import InstrumentId

from nautilus_trader.common.component import LiveClock, Logger

from nautilus_trader.config import InstrumentProviderConfig

from nautilus_trader.adapters.binance.common.enums import BinanceAccountType
from nautilus_trader.adapters.binance.factories import get_cached_binance_http_client
from nautilus_trader.adapters.binance.futures.providers import BinanceFuturesInstrumentProvider


def binance_futures_provider():
    clock = LiveClock()

    client = get_cached_binance_http_client(
        clock=clock,
        account_type=BinanceAccountType.USDT_FUTURE,
    )

    binance_provider = BinanceFuturesInstrumentProvider(
        client=client,
        clock=clock,
        config=InstrumentProviderConfig(load_all=True, log_warnings=True)
    )

    asyncio.run(binance_provider.load_all_async())
    return binance_provider


def binance_futures_instrument_from_pair(provider, pair):
    full_name = InstrumentId.from_str(f"{pair}-PERP.BINANCE")
    return provider.find(full_name)


provider = binance_futures_provider()
binance_futures_instrument_from_pair(provider, "APTUSDT")

I got the following exception

Traceback (most recent call last):
  File "/home/tmp/p/p-dev/./binance_instrument_provider.py", line 39, in <module>
    provider = binance_futures_provider()
               ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tmp/p/p-dev/./binance_instrument_provider.py", line 19, in binance_futures_provider
    client = get_cached_binance_http_client(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/p/p-dev/nautilus/venv/lib/python3.12/site-packages/nautilus_trader/adapters/binance/factories.py", line 86, in get_cached_binance_http_client
    api_key = api_key or get_api_key(account_type, is_testnet)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/p/p-dev/nautilus/venv/lib/python3.12/site-packages/nautilus_trader/adapters/binance/common/credentials.py", line 30, in get_api_key
    return get_env_key("BINANCE_FUTURES_API_KEY")
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/p/p-dev/nautilus/venv/lib/python3.12/site-packages/nautilus_trader/adapters/env.py", line 21, in get_env_key
    raise RuntimeError(f"Environment variable '{key}' not set")
RuntimeError: Environment variable 'BINANCE_FUTURES_API_KEY' not set

With API key it works.

Proposed Solution

Disable the key checking on anonymous endpoints.

Alternatives Considered

Setting the API key. This is not preferred as added complexity.