Small fix for transform program and previous device API + typo (#4696)

**Description of the Change:**

Successive QNode call with the previous device API would generate too
many expand functions. For the previous device the program is
initialized.

pennylane/qnode.py

@@ -982,8 +982,8 @@ def __call__(self, *args, **kwargs) -> qml.typing.Result:
             device_transform_program, config = self.device.preprocess(execution_config=config)
             full_transform_program = self.transform_program + device_transform_program
         else:
-            full_transform_program = self.transform_program
-        # Add the gradient expand to the porgram if necessary
+            full_transform_program = qml.transforms.core.TransformProgram(self.transform_program)
+        # Add the gradient expand to the program if necessary
         if (
             isinstance(self.gradient_fn, qml.transforms.core.TransformDispatcher)
             and self.gradient_fn.expand_transform