Write a function that returns true if there exists at least one number that is larger than or equal to n.
existsHigher([5, 3, 15, 22, 4], 10) ➞ true
existsHigher([1, 2, 3, 4, 5], 8) ➞ false
existsHigher([4, 3, 3, 3, 2, 2, 2], 4) ➞ true
existsHigher([], 5) ➞ false
Return false for an empty array [].