Fix bug in HSTU residual.

PiperOrigin-RevId: 747769363

Author: RecML authors

recml/layers/keras/hstu.py

@@ -471,7 +471,7 @@ def call(
     gated_attn_output = u * normed_attn_output
 
     out = self._output_dense(gated_attn_output)
-    return out + normed_inputs
+    return out + inputs
 
   def get_config(self) -> dict[str, Any]:
     return {