Fix bug when model cannot be partially unloaded.

comfy/model_management.py

@@ -338,8 +338,9 @@ class LoadedModel:
     def model_unload(self, memory_to_free=None, unpatch_weights=True):
         if memory_to_free is not None:
             if memory_to_free < self.model.loaded_size():
-                self.model.partially_unload(self.model.offload_device, memory_to_free)
-                return False
+                freed = self.model.partially_unload(self.model.offload_device, memory_to_free)
+                if freed >= memory_to_free:
+                    return False
         self.model.unpatch_model(self.model.offload_device, unpatch_weights=unpatch_weights)
         self.model.model_patches_to(self.model.offload_device)
         self.weights_loaded = self.weights_loaded and not unpatch_weights