feat: adjust okx ohlcv candle limits

Author: xmatthias

freqtrade/exchange/okx.py

@@ -65,15 +65,22 @@ def ohlcv_candle_limit(
         """
         Exchange ohlcv candle limit
         OKX has the following behaviour:
-        * 300 candles for up-to-date data
-        * 100 candles for historic data
-        * 100 candles for additional candles (not futures or spot).
+        * spot and futures:
+            * 300 candles for regular candles
+        * mark and premium-index:
+            * 300 candles for up-to-date data
+            * 100 candles for historic data
+        * additional data:
+            * 100 candles for additional candles
         :param timeframe: Timeframe to check
         :param candle_type: Candle-type
         :param since_ms: Starting timestamp
         :return: Candle limit as integer
         """
-        if candle_type in (CandleType.FUTURES, CandleType.SPOT) and (
+        if candle_type in (CandleType.FUTURES, CandleType.SPOT):
+            return 300
+
+        if candle_type in (CandleType.MARK, CandleType.PREMIUMINDEX) and (
             not since_ms or since_ms > (date_minus_candles(timeframe, 300).timestamp() * 1000)
         ):
             return 300