Kourtney Kardashian and Kim Kardashian James Devaney/GC Images Kourtney Kardashian is poking fun at sister Kim Kardashian’s infamous diamond earring meltdown. “My diamond earring came off in the ocean and it’s gone,” Kourtney, 44, captioned her Instagram post on Sunday, April 7. Alongside the caption, Kourtney uploaded a pic of her smiling as she swam…