Add missing operator_type (#764)

Author: VincentLanglet

src/Filter/AbstractDateFilter.php

@@ -50,6 +50,7 @@ final public function getFormOptions(): array
             'field_type' => $this->getFieldType(),
             'field_options' => $this->getFieldOptions(),
             'label' => $this->getLabel(),
+            'operator_type' => $this->range ? DateRangeOperatorType::class : DateOperatorType::class,
         ];
     }