Write a function named `longest_sorted_sequence`

that accepts an array of
integers as a parameter and that returns the length of the longest sorted
(non-decreasing) sequence of integers in the array.

For example, if a variable named `$arr`

stores the following values:

$arr = [3, 8, 10, 1, 9, 14, -3, 0, 14, 207, 56, 98, 12];

then the call of `longest_sorted_sequence($arr)`

should return `4`

because the longest sorted sequence in the array has four values in it
(the sequence -3, 0, 14, 207). Note that sorted means non-decreasing, which means that
the sequence could contain duplicates. For example, if the array stores the following values:

$arr = [17, 42, 3, 5, 5, 5, 8, 2, 4, 6, 1, 19];

Then the function would return `5`

for the length of the longest sequence (3, 5, 5, 5, 8).
Your function should return `0`

if passed an empty array, and should return `1`

if passed an array that is entirely in decreasing order or contains only one element.

*Constraints:*

- You may not use any auxiliary data structures (arrays, strings, etc.) to solve this problem.
- Your function should not modify the array that is passed in.