Similar DM for PML grids needs to be maintained after load balance.

[atmyers]

After PR #2665, the default behavior is for the dmap of the PML grids to follow that of the mother grids. However, this correspondence will be broken when load balancing is enabled, because we do not regrid the PML on load balance. When warpx.do_similar_dm_pml=1, we need to also regrid the PML data after a load balance to maintain this relationship.