Ensure public input delta is correct if polynomial virtual size increases (not an issue in ClientIVC just isolated tests)

[maramihali]

The correct construction of the public input delta in compute_public_input_delta depends on the agreement between the "domain_size" value used here and the "num_gates" value used in the construction of the sigma/id polynomials in compute_honk_style_permutation_lagrange_polynomials_from_mapping(). The former happens in the Decider PK constructor and the latter happens in oink so there's no issue unless something changes between those two steps (i.e. this shouldn't apply in the IVC setting because we've fully completed a key before expanding it to accommodate accumulation of a larger circuit). Still, it can come up in more isolated test and would be nice to find a way to systematically ensure these agree.