fix: make filter.lightning.type optional in nowcast filter config

Backend already treats a missing/null lightning.type as "no type
constraint", but the sandbox validator required it whenever a
lightning block was present, causing valid configs to be rejected
with "filter.lightning.type FLASH_CLOUD_TO_GROUND veya PULSE_IN_CLOUD
olmalıdır." Now the check only rejects an explicitly invalid value.

geo_alarm.py

@@ -120,9 +120,13 @@ def load_nowcast_geo_alarm_filter(path: Path) -> dict[str, Any]:
         if not isinstance(lightning, dict):
             raise ConfigurationError("filter.lightning JSON nesnesi olmalıdır.")
         event_type = lightning.get("type")
-        if event_type not in {"FLASH_CLOUD_TO_GROUND", "PULSE_IN_CLOUD"}:
+        if event_type is not None and event_type not in {
+            "FLASH_CLOUD_TO_GROUND",
+            "PULSE_IN_CLOUD",
+        }:
             raise ConfigurationError(
-                "filter.lightning.type FLASH_CLOUD_TO_GROUND veya PULSE_IN_CLOUD olmalıdır."
+                "filter.lightning.type belirtilirse FLASH_CLOUD_TO_GROUND veya "
+                "PULSE_IN_CLOUD olmalıdır."
             )
 
     thunderstorm = config.get("thunderstorm")