Release interfaces on activation failure

[mhubii]

Currently, state / command interfaces are not released on failure:

lbr_fri_ros2_stack/lbr_ros2_control/src/controllers/admittance_controller.cpp

Line 186 in c361620

if (!reference_state_interfaces_()) {

This prevents potential re-activation due to double assignment:

lbr_fri_ros2_stack/lbr_ros2_control/src/controllers/admittance_controller.cpp

Line 235 in c361620

if (joint_position_state_interfaces_.size() != lbr_fri_ros2::N_JNTS) {