Remove redundant error check that the Position is in the mesh that is already performed in get_indices.
Remove redundant error check that the Position is in the mesh that is already performed in get_indices.

amandalund/openmc,mit-crpg/openmc,mit-crpg/openmc,walshjon/openmc,mit-crpg/openmc,shikhar413/openmc,shikhar413/openmc,amandalund/openmc,shikhar413/openmc,walshjon/openmc,amandalund/openmc,paulromano/openmc,mit-crpg/openmc,paulromano/openmc,amandalund/openmc,walshjon/openmc,paulromano/openmc,paulromano/openmc,shikhar413/openmc,walshjon/openmc