Fixed error when receiving NICv1 in example decoder due to mismatch in output

[kestr31]

Currently the current definition of the pms.adsb.nic_v1 is as follows:

• src/pyModeS/decoder/adsb.py

def nic_v1(msg: str, NICs: int) -> tuple[int, None | float, None | float]:
    """Calculate NIC, navigation integrity category, for ADS-B version 1

    Args:
        msg (str): 28 hexdigits string
        NICs (int or string): NIC supplement

    Returns:
        int: NIC, Navigation Integrity Category
        int or string: Horizontal Radius of Containment
        int or string: Vertical Protection Limit
    """
    tc = typecode(msg)
    if tc is None or tc < 5 or tc > 22:
        raise RuntimeError(
            "%s: Not a surface position message (5<TC<8), \
            airborne position message (8<TC<19), \
            or airborne position with GNSS height (20<TC<22)"
            % msg
        )

    NIC = uncertainty.TC_NICv1_lookup[tc]

    if isinstance(NIC, dict):
        NIC = NIC[NICs]

    d_index = uncertainty.NICv1.get(NIC, None)
    Rc, VPL = uncertainty.NA, uncertainty.NA

    if d_index is not None:
        index = d_index.get(NICs, None)
        if index is not None:
            Rc = index["Rc"]
            VPL = index["VPL"]

    return NIC, Rc, VPL

which returns NIC, Rc, and VPL. However, the example decoder is set for the case of NICv1 as:

• src/pyModeS/streamer/decode.py

ac["Rc"], ac["VPL"] = pms.adsb.nic_v1(msg, ac["nic_s"])

to receive only Rc and VPL. Due to this mismatch in output, the example decoder crashed on the case of NICv1. Since it is the example decoder, this seems not to be a critical issue. But, just to make it right, I write this PR.

Thank you in advance for your review, and please check this PR whenever available. Thank you.