tests: remove unused imports

tests/exchange/test_bybit.py

@@ -1,11 +1,8 @@
 from datetime import datetime, timedelta, timezone
 from unittest.mock import MagicMock
 
-import pytest
-
 from freqtrade.enums.marginmode import MarginMode
 from freqtrade.enums.tradingmode import TradingMode
-from freqtrade.exceptions import OperationalException
 from tests.conftest import EXMS, get_mock_coro, get_patched_exchange, log_has
 from tests.exchange.test_exchange import ccxt_exceptionhandlers