Bug: Adding a gpx track may change the georef of a route

**Describe the bug**
When a gpx track is uploaded to a route, it sometimes also change the georef of the route. This seems to happen when the gpx track contains not only a track, but also a waypoint.

See an example of a problematic gpx : [2025-02-02 0920__20250202_0920-breche.txt](https://github.com/user-attachments/files/19649816/2025-02-02.0920__20250202_0920-breche.txt)

**Expected behavior**
When a gpx file is uploaded, only the track should be taken into account and not potential waypoints. These are very unlikely to correspond to [the rules of the georef of a route](https://www.camptocamp.org/articles/107007/fr/aide-topoguide-cartographie-georeferencements#conventions-pour-la-geolocalisation-ponctuelle-des-itineraires).