Make it so that upscalers are not repeated when restarting UI.

webui.py

@@ -1,4 +1,5 @@
 import os
+import sys
 import threading
 import time
 import importlib
@@ -55,8 +56,8 @@ def initialize():
     gfpgan.setup_model(cmd_opts.gfpgan_models_path)
     shared.face_restorers.append(modules.face_restoration.FaceRestoration())
 
+    modelloader.list_builtin_upscalers()
     modules.scripts.load_scripts()
-
     modelloader.load_upscalers()
 
     modules.sd_vae.refresh_vae_list()
@@ -169,23 +170,22 @@ def webui():
         modules.script_callbacks.app_started_callback(shared.demo, app)
 
         wait_on_server(shared.demo)
+        print('Restarting UI...')
 
         sd_samplers.set_samplers()
 
-        print('Reloading extensions')
         extensions.list_extensions()
 
         localization.list_localizations(cmd_opts.localizations_dir)
 
-        print('Reloading custom scripts')
+        modelloader.forbid_loaded_nonbuiltin_upscalers()
         modules.scripts.reload_scripts()
         modelloader.load_upscalers()
 
-        print('Reloading modules: modules.ui')
-        importlib.reload(modules.ui)
-        print('Refreshing Model List')
+        for module in [module for name, module in sys.modules.items() if name.startswith("modules.ui")]:
+            importlib.reload(module)
+
         modules.sd_models.list_models()
-        print('Restarting Gradio')
 
 
 if __name__ == "__main__":