Include electric field for time-dependent multipole kicks

We should modify `multipole_kick!` so that if the multipoles are of type `Function`, then a corresponding electric field kick is also included. also the unpacking step should make it so that DKD is therefore used whenever any multipole is time-dependent

Start by reading `multipole_kick!` and the unpacking step to understand how function-valued multipoles are identified and how the integration scheme is selected. Implement the requested electric-field kick and ensure DKD is selected whenever any multipole is time-dependent; verify the relevant Julia tests or simulation behavior if available.

Written by the indexing model from the issue text.