Muslim women in Kuwait are not required to wear abayas. (Nor are they required to cover their hair). They can wear Western clothing, and that outfit would be perfectly acceptable if it came in Chantal's size. Which of course it doesn't.
The Koran says: "O Prophet, tell your wives and daughters, and the believing women, to cover themselves with a loose garment. They will thus be recognised and no harm will come to them."
Chantal's abayas are not loose garments. Her attire would be more in keeping with the Koran if she wore an outfit like the one in the picture than those abayas that fit her like a sausage casing.
It will be interesting to see what Western clothing she will start wearing in the next few months since Salah supposedly told her to stop wearing the abayas. As discussed before, Torrid ships to foreign countries, but she is probably busting out of their largest size. Maybe she can get something on Amazon or have something custom-made in Kuwait. Time will tell.