fix: revert _class_name to array format for custom pipeline loading

model_index.json

@@ -1,5 +1,8 @@
 {
-  "_class_name": "KiwiEditPipeline",
+  "_class_name": [
+    "pipeline_kiwi_edit",
+    "KiwiEditPipeline"
+  ],
   "_diffusers_version": "0.32.0",
   "processor": [
     "transformers",
@@ -24,6 +27,5 @@
   "source_embedder": [
     "conditional_embedder",
     "ConditionalEmbedder"
-  ],
-  "_custom_pipeline": "pipeline_kiwi_edit"
+  ]
 }