Merge branch 'hotfix/fix_module_option_null' into 'release/2.3.0'

Fix module option null

See merge request metamodels/core!293

src/CoreBundle/Contao/Hooks/AbstractContentElementAndModuleCallback.php

@@ -387,7 +387,7 @@ protected function buildFilterParamsFor(DC_Table $dataContainer, $elementName)
             return;
         }
 
-        $translatedNull = $this->translator->trans('filter_option.null', [], self::$tableName);
+        $translatedNull = $this->translator->trans('filter_option.null', [], static::$tableName);
 
         $collection = $this->filterFactory->createCollection($filterId);
         $dca        = $collection->getParameterDCA();