update trade object as optional parameter

docs/strategy_migration.md

@@ -271,7 +271,7 @@ New string argument `side` - which can be either `"long"` or `"short"`.
 
 ``` python hl_lines="3"
 class AwesomeStrategy(IStrategy):
-    def custom_entry_price(self, pair: str, trade: 'Trade', current_time: datetime, proposed_rate: float,
+    def custom_entry_price(self, pair: str, current_time: datetime, proposed_rate: float,
                            entry_tag: Optional[str], **kwargs) -> float:
       return proposed_rate
 ```
@@ -280,7 +280,7 @@ After:
 
 ``` python hl_lines="3"
 class AwesomeStrategy(IStrategy):
-    def custom_entry_price(self, pair: str, trade: 'Trade', current_time: datetime, proposed_rate: float,
+    def custom_entry_price(self, pair: str, trade: Optional[Trade], current_time: datetime, proposed_rate: float,
                            entry_tag: Optional[str], side: str, **kwargs) -> float:
       return proposed_rate
 ```

freqtrade/freqtradebot.py

@@ -938,7 +938,7 @@ class FreqtradeBot(LoggingMixin):
             custom_entry_price = strategy_safe_wrapper(self.strategy.custom_entry_price,
                                                        default_retval=enter_limit_requested)(
                 pair=pair,
-                trade=trade,  # type: ignore[arg-type]
+                trade=trade,
                 current_time=datetime.now(timezone.utc),
                 proposed_rate=enter_limit_requested, entry_tag=entry_tag,
                 side=trade_side,

freqtrade/strategy/interface.py

@@ -395,7 +395,7 @@ class IStrategy(ABC, HyperStrategyMixin):
         """
         return self.stoploss
 
-    def custom_entry_price(self, pair: str, trade: Trade,
+    def custom_entry_price(self, pair: str, trade: Optional[Trade],
                            current_time: datetime, proposed_rate: float,
                            entry_tag: Optional[str], side: str, **kwargs) -> float:
         """