add a default engine to the AutoGGUFModel

Author: maziyarpanahi

src/main/scala/com/johnsnowlabs/nlp/annotators/seq2seq/AutoGGUFModel.scala

@@ -156,6 +156,8 @@ class AutoGGUFModel(override val uid: String)
 
   private[johnsnowlabs] def setEngine(engineName: String): this.type = set(engine, engineName)
 
+  setDefault(engine -> LlamaCPP.name)
+  
   override def onWrite(path: String, spark: SparkSession): Unit = {
     super.onWrite(path, spark)
     getModelIfNotSet.saveToFile(path)