Unload clip on demand and workaround memory leak (#1283)

apps/stable_diffusion/web/utils/global_obj.py

@@ -32,6 +32,11 @@ def set_sd_status(value):
     _sd_obj.status = value
 
 
+def set_sd_ondemand(value):
+    global _sd_obj
+    _sd_obj.ondemand = value
+
+
 def set_cfg_obj(value):
     global _config_obj
     _config_obj = value