DJS/remove period from csdm dimension for simulations

[deepanshs]

Bug fix where dimensions were returned as periodic dimensions.

from mrsimulator import Simulator, SpinSystem, Site
from mrsimulator.method.lib import BlochDecaySpectrum
import matplotlib.pyplot as plt

H_site = Site(isotope="1H", shielding_symmetric={"zeta": 13.89, "eta": 0.25})
spin_system = SpinSystem(sites=[H_site])

static = BlochDecaySpectrum(channels=["1H"])
mas = BlochDecaySpectrum(channels=["1H"], rotor_frequency=1000)  # in Hz

sim = Simulator(spin_systems=[spin_system], methods=[static, mas])
sim.run()

print(sim.methods[0].simulation.x[0].period)

return period as np.inf Hz

[deepanshs]

@mccarthy677 can you check if this fixes the baseline offset you saw related to fft?