PHP 8.1 Worksheet->removeAutoFilter setting setRange to null result in errors

[brainfoolong]

This is:

• a bug report

What is the expected behavior?

No error :)

What is the current behavior?

strrpos(): Passing null to parameter #1 ($haystack) of type string is deprecated

What are the steps to reproduce?

On a sheet, call $sheet->removeAutoFilter()
This will internally call $this->autoFilter->setRange(null) where null will cause the error.
I temporarily fixed it with replacing it with an empty string, but i am not sure if this is a correct fix.

Most minimal example

$spreadsheet = new Spreadsheet();
$sheet = $spreadsheet->getSheet(0);
$sheet->removeAutoFilter();

Which versions of PhpSpreadsheet and PHP are affected?

Current Master as well as current stable release. The master have some significant changes to stable but this error is still not fixed.