[IOS-XE] "show ntp assocations" parser does not correctly summarize clock state

[ChristopherJHart]

The value of the clock_state.system_status.clock_state key in the IOS-XE show ntp associations has an incorrect value with some permutations of output.

For example, with the below output:

  address         ref clock       st   when   poll reach  delay  offset   disp
*~192.0.2.1       192.0.2.2        2    676   1024   377  0.117  -3.705  1.090
+~192.0.2.10      .GNSS.           1    811   1024   377  0.319  -3.649  1.053
 ~192.0.2.20      127.0.0.1       16    375   1024     0  0.000   0.000 15937.
 * sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured

Results in the below parsed data:

{
    "clock_state": {
        "system_status": {
            "associations_address": "192.0.2.1",
            "associations_local_mode": "client",
            "clock_offset": -3.705,
            "clock_refid": "192.0.2.2",
            "clock_state": "unsynchronized",
            "clock_stratum": 2,
            "root_delay": 0.117,
        },
    },
    "peer": {
        "192.0.2.1": {
            "local_mode": {
                "client": {
                    "configured": True,
                    "delay": 0.117,
                    "jitter": 1.09,
                    "local_mode": "client",
                    "mode": "synchronized",
                    "offset": -3.705,
                    "poll": 1024,
                    "reach": 377,
                    "receive_time": 676,
                    "refid": "192.0.2.2",
                    "remote": "192.0.2.1",
                    "stratum": 2,
                },
            },
        },
        "192.0.2.10": {
            "local_mode": {
                "client": {
                    "configured": True,
                    "delay": 0.319,
                    "jitter": 1.053,
                    "local_mode": "client",
                    "mode": "candidate",
                    "offset": -3.649,
                    "poll": 1024,
                    "reach": 377,
                    "receive_time": 811,
                    "refid": ".GNSS.",
                    "remote": "192.0.2.10",
                    "stratum": 1,
                },
            },
        },
        "192.0.2.20": {
            "local_mode": {
                "client": {
                    "configured": True,
                    "delay": 0.0,
                    "jitter": 15937.0,
                    "local_mode": "client",
                    "mode": "unsynchronized",
                    "offset": 0.0,
                    "poll": 1024,
                    "reach": 0,
                    "receive_time": 375,
                    "refid": "127.0.0.1",
                    "remote": "192.0.2.20",
                    "stratum": 16,
                },
            },
        },
    },
}

We can see that the value of the clock_state.system_status.clock_state indicates the device is unsychronized, even though it's synchronized.