Issue #3270514: Call to a member function getDataDefinition() on bool

Prevent error if $field is False

src/Plugin/facets/processor/ListItemProcessor.php

@@ -128,7 +128,7 @@ class ListItemProcessor extends ProcessorPluginBase implements BuildProcessorInt
     }
     // Fields defined in code don't can't be loaded from storage so check the
     // fields property path and see if its part of the base fields.
-    elseif ($field->getDataDefinition() instanceof FieldItemDataDefinition) {
+    elseif ($field && $field->getDataDefinition() instanceof FieldItemDataDefinition) {
       $fieldDefinition = $field->getDataDefinition()
         ->getFieldDefinition();
       $referenced_entity_name = sprintf(