fix: improve datetime for trade_list_to_dataframe

closes freqtrade#12388

Author: xmatthias

freqtrade/data/btanalysis/bt_fileutils.py

@@ -511,8 +511,8 @@ def trade_list_to_dataframe(trades: list[Trade] | list[LocalTrade]) -> pd.DataFr
     """
     df = pd.DataFrame.from_records([t.to_json(True) for t in trades], columns=BT_DATA_COLUMNS)
     if len(df) > 0:
-        df["close_date"] = pd.to_datetime(df["close_date"], utc=True)
-        df["open_date"] = pd.to_datetime(df["open_date"], utc=True)
+        df["close_date"] = pd.to_datetime(df["close_timestamp"], unit="ms", utc=True)
+        df["open_date"] = pd.to_datetime(df["open_timestamp"], unit="ms", utc=True)
         df["close_rate"] = df["close_rate"].astype("float64")
     return df