Given a list of prices prices and a "supposed" total t, return True if there is a hidden fee added to the total (i.e. the total is greater than the sum of prices), otherwise return False.
has_hidden_fee(["$2", "$4", "$1", "$8"], "$15") ➞ False
has_hidden_fee(["$1", "$2", "$3"], "$6") ➞ False
has_hidden_fee(["$1"], "$4") ➞ True