Never pass enable_xla=False or native_serialization=False in tests (k…

…eras-team#20664)

These are invalid options in the latest version of jax2tf, they
will just immediately throw.

keras/src/export/export_lib_test.py

@@ -275,7 +275,7 @@ def test_input_signature_error(self):
             is_static=(True, False),
             jax2tf_kwargs=(
                 None,
-                {"enable_xla": False, "native_serialization": False},
+                {"enable_xla": True, "native_serialization": True},
             ),
         )
     )