A list is positive dominant if it contains strictly more unique positive values than unique negative values. Write a function that returns True if a list is positive dominant.
is_positive_dominant([1, 1, 1, 1, -3, -4]) ➞ False
# There is only 1 unique positive value (1).
# There are 2 unique negative values (-3, -4)
is_positive_dominant([5, 99, 832, -3, -4]) ➞ True
is_positive_dominant([5, 0]) ➞ True
is_positive_dominant([0, -4, -1]) ➞ False
0 counts as neither a positive nor a negative value.