[parallel] specialize canCommunicate capability for UGGrid

Bernd Flemischrequested to merge
cherry-pick-b524acb3 into feature/restart-from-vtk

This hasn't happened until now in dune-grid such that AMG uses sequential traits for a parallel UGGrid. Implement this as a temporary solution until it is fixed upstream.

(cherry picked from commit b524acb3)

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