FIX: discard argument allowLiquid in function PyModel1D.__init__()

[Dengda98]

allowLiquid will be a deprecated argument. For compatibility, just keep allowLiquid and won't use it.

class PyModel1D:
    def __init__(self, modarr0:np.ndarray, depsrc:float, deprcv:float, allowLiquid:bool=True, ...)