BUG: Satellite Tracker crashes

[gvimlag]

PROBLEM:
If two or more satellites are tracked by "Satellite Tracker", selecting "Next" (sort by "Next") BEFORE starting "Satellite Tracker" causes a crash.

EXAMPLE: (The sequence below is the minimum needed to reproduce the crash. All other components have been stripped out.)

rm -rf ~/.config/f4exb                #clean initial conditions
/opt/install/sdrangel/bin/sdrangel    #start sdrangel
  Add features
    Satellite Tracker
    Apply
    Close
  Select satellites
    <Add "NOAA 15" to "Satellites to track">    #must have two or more satellites listed under "Satellites to track"
    OK
  <in "Satellite Date" Window, select "Next">   #sort by "Next"
  start/stop tracking                           #start satellite tracking
<CRASH>

Terminal:

<click: start/stop tracking>
2022-10-09 17:50:12.405 (D) SatelliteTracker::handleMessage: MsgStartStop: start: true
2022-10-09 17:50:12.405 (D) SatelliteTracker::start
2022-10-09 17:50:12.405 (W) FeatureWebAPIUtils::mapSetDateTime: no Map feature
2022-10-09 17:50:12.406 (D) SatelliteTrackerWorker::startWork
2022-10-09 17:50:12.406 (D) SatelliteTrackerWorker::applySettings:  m_target:  "ISS"  m_satellites:  ("ISS", "NOAA 15")  m_dateTime:  ""  m_utc:  false  m_updatePeriod:  1  force:  true
2022-10-09 17:50:12.413 (D) SatelliteTrackerWorker: Current time:  "2022-10-09T23:50:12.407Z"
2022-10-09 17:50:12.414 (D) SatelliteTrackerWorker: New AOS:  "NOAA 15"  new:  QDateTime(2022-10-10 06:57:44.000 UTC Qt::UTC)  old:  QDateTime(Invalid)
2022-10-09 17:50:12.414 (D) SatelliteTrackerWorker: New LOS:  "NOAA 15"  new:  QDateTime(2022-10-10 07:10:17.000 UTC Qt::UTC)  old:  QDateTime(Invalid)
2022-10-09 17:50:12.414 (D) SatelliteTrackerWorker:: Interval to LOS  26404593
2022-10-09 17:50:12.447 (D) SatelliteTrackerWorker: Current time:  "2022-10-09T23:50:12.407Z"
2022-10-09 17:50:12.448 (D) SatelliteTrackerWorker: New AOS:  "ISS"  new:  QDateTime(2022-10-10 09:39:18.000 UTC Qt::UTC)  old:  QDateTime(Invalid)
2022-10-09 17:50:12.448 (D) SatelliteTrackerWorker: New LOS:  "ISS"  new:  QDateTime(2022-10-10 09:47:24.000 UTC Qt::UTC)  old:  QDateTime(Invalid)
2022-10-09 17:50:12.448 (D) SatelliteTrackerWorker:: Interval to LOS  35831593
Segmentation fault

SYSTEM:

  Hardware: x86 64-bit
  OS:       Debian 11 (bullseye) 64-bit
  SDRangel: (compiled from source following "https://github.com/f4exb/sdrangel/wiki/Compile-from-source-in-Linux")
    Version 7.8.0-10-gc6496b11f
    Build info: Qt 5.15.2 64 bits
    DSP Rx 16 bits    Tx 16 bits
      Included plugins for "Hardware dependencies":
        RTL-SDR
      Included plugins for "Soapy SDR":
        RTL-SDR
        Soapy Remote