[PricesManager] fix recent trade mark price overriding exchange mark price

Author: techfreaque

octobot_trading/exchange_data/prices/prices_manager.py

@@ -70,12 +70,13 @@ def set_mark_price(self, mark_price, mark_price_source) -> bool:
 
         # set mark price value if MarkPriceSources.RECENT_TRADE_AVERAGE.value has already been updated
         elif mark_price_source == enums.MarkPriceSources.RECENT_TRADE_AVERAGE.value:
-            if self.mark_price_from_sources.get(enums.MarkPriceSources.RECENT_TRADE_AVERAGE.value, None) is not None:
-                self._set_mark_price_value(mark_price)
-                is_mark_price_updated = True
-            else:
-                # set time at 0 to ensure invalid price but keep track of initialization
-                self.mark_price_from_sources[mark_price_source] = (mark_price, 0)
+            if enums.MarkPriceSources.EXCHANGE_MARK_PRICE.value not in self.mark_price_from_sources:
+                if self.mark_price_from_sources.get(enums.MarkPriceSources.RECENT_TRADE_AVERAGE.value, None) is not None:
+                    self._set_mark_price_value(mark_price)
+                    is_mark_price_updated = True
+                else:
+                    # set time at 0 to ensure invalid price but keep track of initialization
+                    self.mark_price_from_sources[mark_price_source] = (mark_price, 0)
 
         # set mark price value if other sources have expired
         elif mark_price_source in (enums.MarkPriceSources.TICKER_CLOSE_PRICE.value,