fix(wildlife): point the Acartia card link only at acartia.io

The card's "Acartia" link was built from the contributor-supplied
photo_url, so any https site could appear labelled as Acartia. Acartia
has no documented per-sighting page, so the source link is now always
the Acartia site, on the server projection and again in the card.
The separate "Open on Acartia" fallback link is no longer needed.

src/i18n/locales/fr.json

@@ -3228,7 +3228,6 @@
   "Loading photo...": "Chargement de la photo…",
   "Photo unavailable": "Photo indisponible",
   "Location obscured to a 0.2° cell": "Localisation masquée dans une cellule de 0,2°",
-  "Open on Acartia ↗": "Ouvrir sur Acartia ↗",
   "Photo of {name}": "Photo de {name}",
   "Acartia": "Acartia",
   "CC BY 4.0": "CC BY 4.0",