When Apple debuts new iPhones on Tuesday, analysts say its biggest challenge will be to ride out another ho-hum launch as rivals have skated past it in embedding artificial intelligence into their products and services. The biggest draw this year could be a rumoured “iPhone Air”, a phone slimmer than what Apple has sold before and taking its name from the company’s slender laptop, MacBook Air. Apple would need to iron out how to pack batteries and cameras into a thinner device, analysts said,...