[BUG] ADAPTSolver does not update the optimal_* attributes when max_cycles>1

[alexfleury-sb]

Issue: Bug Report

Expected Behavior
ADAPTSolver should update the optimal_* attributes after simulate has been called.

Current Behavior
When max_cycles>1 and the energy converges in less than max_cycles steps, the optimal attributes are not updated (var_params, circuit, etc.). They stay as None.

Steps to Reproduce (minimal example)

1. Perform ADAPT-VQE

from tangelo.algorithms import ADAPTSolver
from tangelo.molecule_library import mol_H2_sto3g

solver = ADAPTSolver({
    "molecule": mol_H2_sto3g,
    "max_cycles": 2,
    "verbose": True
})
solver.build()
solver.simulate()

circuit = solver.optimal_circuit
print(circuit)

2. Call optimal_circuit. In the previous example, circuit is None.

Environment
Ubuntu - python 3.10, latest commit of the develop branch

[alexfleury-sb]

Is fixed with #241 (only the optimal_circuit was not updated).