chore: fix phpstan errors

src/Service/InsuranceManager.php

@@ -43,7 +43,7 @@ class InsuranceManager
     {
         $cacheKey = 'selectable_insurances_'.$travel->id;
 
-        return $this->selectableInsurancesCache[$cacheKey] ??= $this->filterNonComplementary($travel->insurances ?? []);
+        return $this->selectableInsurancesCache[$cacheKey] ??= $this->filterNonComplementary($travel->insurances);
     }
 
     /**