fix qft test

[splch]

steps to reproduce:

import numpy as np
from qubit_simulator import QubitSimulator


def apply_qft(simulator):
    num_qubits = simulator.num_qubits
    for target_qubit in range(num_qubits):
        # Apply Hadamard gate to the target qubit
        simulator.H(target_qubit)
        # Apply controlled phase gates to the target qubit
        for control_qubit in range(target_qubit + 1, num_qubits):
            phase_angle = 2 * np.pi / (2 ** (control_qubit - target_qubit + 1))
            simulator.CU(target_qubit, control_qubit, 0, 0, phase_angle)


simulator = QubitSimulator(3)

# Create a random initial state vector and normalize it
random_state = np.random.rand(8) + 1j * np.random.rand(8)
random_state /= np.linalg.norm(random_state)

# Set the random state as the initial state in the simulator
simulator.state_vector = random_state.copy()

# Apply QFT in the simulator
apply_qft(simulator)

# Compute the expected result using NumPy's FFT and normalize
fft_result = np.fft.fft(random_state) / np.sqrt(8)

# Compare the state vectors
print(f"simulator = {simulator.state_vector}")
print(f"np.fft.fft = {fft_result}")

simulator = [ 0.7119692 +0.47623858j -0.28574069-0.11805649j 0.24575554+0.09035911j
-0.04866791-0.15844743j -0.12457145-0.00268797j -0.02088207-0.09257858j
0.18633583+0.01814583j 0.04555531-0.11410155j]
np.fft.fft = [ 0.7119692 +0.47623858j 0.04555531-0.11410155j -0.04866791-0.15844743j
-0.02088207-0.09257858j -0.28574069-0.11805649j 0.18633583+0.01814583j
0.24575554+0.09035911j -0.12457145-0.00268797j]