Fix error during faction loading

ForceGroup loading failed due to wrong unit parsing and prevented factions without naval units to load before the first faction with naval units got loaded (this affected the Allies 1940 and 44 factions)

game/armedforces/forcegroup.py

@@ -281,8 +281,15 @@ class ForceGroup:
                 logging.error(f"ForceGroup {name} has no valid tasking")
                 continue
 
-            units = [UnitType.named(unit) for unit in data.get("units")]
-            if not units:
+            units: list[UnitType[Any]] = []
+            for unit in data.get("units"):
+                if GroundUnitType.exists(unit):
+                    units.append(GroundUnitType.named(unit))
+                elif ShipUnitType.exists(unit):
+                    units.append(ShipUnitType.named(unit))
+                else:
+                    logging.error(f"Unit {unit} of ForceGroup {name} is invalid")
+            if len(units) == 0:
                 logging.error(f"ForceGroup {name} has no valid units")
                 continue
 

game/dcs/unittype.py

@@ -45,7 +45,7 @@ class UnitType(ABC, Generic[DcsUnitTypeT]):
 
     @classmethod
     def named(cls, name: str) -> UnitType[Any]:
-        return cls._by_name[name]
+        raise NotImplementedError
 
     @classmethod
     def for_dcs_type(cls, dcs_unit_type: DcsUnitTypeT) -> Iterator[UnitType[Any]]:
@@ -69,3 +69,13 @@ class UnitType(ABC, Generic[DcsUnitTypeT]):
     @cached_property
     def eplrs_capable(self) -> bool:
         return getattr(self.dcs_unit_type, "eplrs", False)
+
+    @classmethod
+    def exists(cls, name: str) -> bool:
+        if not cls._loaded:
+            cls._load_all()
+        try:
+            cls.named(name)
+            return True
+        except (KeyError, AssertionError):
+            return False