input: Write a python function to determine if one array is entirely contained within another array.
  assert is_subset([11, 1, 13, 21, 3, 7], 6, [11, 3, 7, 1], 4) == True
  assert is_subset([1, 2, 3, 4, 5, 6], 6, [1, 2, 4], 3) == True
  assert is_subset([10, 5, 2, 23, 19], 5, [19, 5, 3], 3) == False
output: def is_subset(arr1, m, arr2, n):
      set1 = set(arr1)
      set2 = set(arr2)
      return set2.issubset(set1)