Fix bugs for Bosonic Homodyne measurement and marginal function

[Hugh-888]

Fix bug for bosonic homodyne measurement and marginal function

1. bosonic homodyne measurement

cir = dq.QumodeCircuit(nmode=2, init_state='vac', cutoff=3, backend='bosonic')
cir.cat(wires=0, r=1)
state = cir()
measure_re = cir.measure_homodyne(wires=[0,1], shots=100)
print(measure_re.shape)

2. bosonic marginal function

cir = dq.QumodeCircuit(nmode=2, init_state='vac', cutoff=3, backend='bosonic')
cir.cat(wires=0, r=1)
state = cir()
s = dq.BosonicState(state, nmode=2)
qvec = torch.linspace(-5, 5, 200)
pvec = torch.linspace(-5, 5, 200)
marginal = s.marginal(wire=0, qvec=qvec, phi=0, plot=True)