put refiner into main UI, into the new accordions section

add VAE from main model into infotext, not from refiner model
option to make scripts UI without gr.Group
fix inconsistencies with refiner when usings samplers that do more denoising than steps

modules/sd_models.py

@@ -147,6 +147,9 @@ re_strip_checksum = re.compile(r"\s*\[[^]]+]\s*$")
 
 
 def get_closet_checkpoint_match(search_string):
+    if not search_string:
+        return None
+
     checkpoint_info = checkpoint_aliases.get(search_string, None)
     if checkpoint_info is not None:
         return checkpoint_info