Please solve the programming task below using a self-contained code snippet in a markdown code block.

Given an integer array arr, remove a subarray (can be empty) from arr such that the remaining elements in arr are non-decreasing.
Return the length of the shortest subarray to remove.
A subarray is a contiguous subsequence of the array.
 
Please complete the following python code precisely:
```python
class Solution:
    def findLengthOfShortestSubarray(self, arr: List[int]) -> int:
```