male lions are harier than the females, and as you've probably noticed, apart from vitani, tama, kula and a few aléatoire outlander lionesses, all the lionesses have no hair. Disney might have wanted to get this point across, and to make the lionesses plus feminine, took away the whiskers.
Th lionesses don't have whiskers for these obvious reasons (1) Disney isn't quite realistic (2) It makes them plus feminine Men's beards are called "whiskers" So this could also be to distinguish the males/lions from the females/lionesses. Also the males' beards look like mustaches as well. Aka: That's a guy thing
It makes them plus feminine as where the whiskers are supposed to refer to mustaches. The whiskers work alongside the manes/beards to help distinguish the males from females in the pride. Disney isn't realistic either.
Fun fact: in real life all lionesses have whiskers.