check block-restriction in FEProblemBase::duplicateVariableCheck

[jmeier]

Currently, in FEProblemBase::duplicateVariableCheck Moose checks that order and family is matching. In the same function, Moose does no checks on the block-restriction. However, it would be very good if Moose would also check the block restriction.

Furthermore, the error message on family and order should be more verbose and give more information.

Originally posted by in #28560 (comment)