Fix #6409 (#6410)

* Update value_guided_sampling.py

Fix #6409

* Comply code style

---------
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

src/diffusers/experimental/rl/value_guided_sampling.py

@@ -49,10 +49,9 @@ class ValueGuidedRLPipeline(DiffusionPipeline):
         env,
     ):
         super().__init__()
-        self.value_function = value_function
-        self.unet = unet
-        self.scheduler = scheduler
-        self.env = env
+
+        self.register_modules(value_function=value_function, unet=unet, scheduler=scheduler, env=env)
+
         self.data = env.get_dataset()
         self.means = {}
         for key in self.data.keys():