Keep the original representation when the service does not provide a better circuit.

[victor-villar]

When subcircuits are sent to the service for optimization, if the return circuit is equal/worse that the original one, we do not replace it. However, instead of keeping the original subcircuit, we keep the representation coming from the collector. For example, when we collect a subcircuit of permutations, instead of having the original circuit we use an intermediate representation which is a permutation block. If we do not get a better cirucit, we leave that instead of the original set of permutations. Although the circuit is the same, the representation is not.