Sondehub: same position after gap

[rs1729]

devel20231110

After a gap of 20 minutes the last position/velocity was recycled and resent to sondehub. frame 2101:

    {
        "software_name": "rdzTTGOsonde",
        "software_version": "devel20231110",
        "uploader_callsign": "SQxxx",
        "time_received": "2024-02-05T16:49:01.000Z",
        "manufacturer": "Vaisala",
        "serial": "V1010258",
        "datetime": "2024-02-05T16:49:18.000Z",
        "lat": 52.20412,
        "lon": 14.19055,
        "alt": 1424.09473,
        "frequency": 405.1,
        "vel_h": 27.88741,
        "vel_v": 4.97614,
        "heading": 106.14401,
        "rssi": -107.5,
        "frame": 2101,
        "type": "RS41",
        "sats": 8,
        "batt": 2.9,
        "position": "52.20412,14.19055",
    },

frame 3462:

    {
        "software_name": "rdzTTGOsonde",
        "software_version": "devel20231110",
        "uploader_callsign": "SQxxx",
        "time_received": "2024-02-05T17:11:42.000Z",
        "manufacturer": "Vaisala",
        "serial": "V1010258",
        "datetime": "2024-02-05T17:11:59.000Z",
        "lat": 52.20412,
        "lon": 14.19055,
        "alt": 1424.09473,
        "frequency": 405.1,
        "vel_h": 27.88741,
        "vel_v": 4.97614,
        "heading": 106.14401,
        "rssi": -106.5,
        "frame": 3462,
        "type": "RS41",
        "sats": 8,
        "batt": 2.8,
        "position": "52.20412,14.19055",
    },

[rs1729]

Perhaps similar problem: V3750539 https://testing.v2.sondehub.org/#!mt=Mapnik&mz=12&qm=3h&mc=51.16557,5.64354&f=V3750539&q=V3750539

cf. https://github.com/dl9rdz/rdz_ttgo_sonde/issues/390 If there is no valid position, the receiver should not upload a new frame with old GPS data to Sondehub as different receivers might have different last positions.