Core: add Location.is_event property (#2968)

BaseClasses.py

@@ -1075,6 +1075,11 @@ class Location:
     def __lt__(self, other: Location):
         return (self.player, self.name) < (other.player, other.name)
 
+    @property
+    def is_event(self) -> bool:
+        """Returns True if the address of this location is None, denoting it is an Event Location."""
+        return self.address is None
+
     @property
     def native_item(self) -> bool:
         """Returns True if the item in this location matches game."""