Fix: Make country name filter failure tolerant

src/BusProNet/DataProvider/CountryDataProvider.php

@@ -32,8 +32,12 @@ class CountryDataProvider
         return $countries;
     }
 
-    public function get(string $token): ?Country
+    public function get(?string $token): ?Country
     {
+        if (null === $token) {
+            return null;
+        }
+
         return $this->getAll()[$token] ?? null;
     }
 }

src/Twig/AppRuntime.php

@@ -36,7 +36,7 @@ class AppRuntime implements RuntimeExtensionInterface
         return sprintf('Offizielle %slehrer*innenlizenz', ucfirst(strtolower($type)));
     }
 
-    public function bpnCountryLabel(string $token, string $property = 'name'): string
+    public function bpnCountryLabel(?string $token, string $property = 'name'): string
     {
         $country = $this->countries->get($token);