fix: make connection nullable

Author: Rocksheep

src/IndexedRecord.php

@@ -19,7 +19,7 @@ class IndexedRecord extends Model
      */
     public function __construct(array $attributes = [])
     {
-        $this->connection = Config::string('laravel-fulltext.db_connection');
+        $this->connection = Config::string('laravel-fulltext.db_connection') ?? null;
 
         parent::__construct($attributes);
     }