I wouldn't say "best" because it depends a lot on what kind of fight you're interested in. Say striking (karate), or grappling (judo), and even weapons (kendo). Though Capoeira both looks super cool and also teaches you some downright brutal moves that don't rely too much on upper body strength, and people in Brazil (specially on the regions it's practised more) are generally on the shorter side. It also comes with a more culture and community focused approach, whereas most martial arts clubs (in my experience) focus mostly on beating the shit out of sandbags and doing tournaments. It also has less gymbros and weebs.

But lots of good martial arts were developed with shorter people in mind, if not by actual short people. Funakoshi, the developer of Shotokan Karate, is believed to have been around 1.55m tall, and Maeda from BJJ was also around 1.65. I'm very amateurish on this but if you're short you might want to avoid striking martial arts that rely too much on throwing punches.