Energy trajectory key is also required in else block. [ci skip]

Author: lohedges

src/sire/mol/_dynamics.py

@@ -492,11 +492,11 @@ def _exit_dynamics_block(
                         zip(lambda_windows, rest2_scale_factors)
                     ):
                         if lambda_value != sim_lambda_value:
+                            key = f"{lambda_value:.5f}"
                             if (
                                 not has_lambda_index
                                 or abs(lambda_index - i) <= num_energy_neighbours
                             ):
-                                key = f"{lambda_value:.5f}"
                                 self._omm_mols.set_lambda(
                                     lambda_value,
                                     rest2_scale=rest2_scale,