Adding PHP 8.5 to the PHP version matrix for tests

[escopecz]

See #447

I was able to replicate on PHP 8.5 when enabling the deprecation notices in PHPUNIT:

https://github.com/1up-lab/OneupUploaderBundle/actions/runs/20812002250/job/59778283160?pr=448

  83x: ArrayIterator::__construct(): Using an object as a backing array for ArrayIterator is deprecated, as it allows violating class constraints and invariants
    6x in FineUploaderTest::testChunkedUpload from Oneup\UploaderBundle\Tests\Controller
    6x in FineUploaderTest::testEvents from Oneup\UploaderBundle\Tests\Controller
    6x in PluploadTest::testChunkedUpload from Oneup\UploaderBundle\Tests\Controller
    6x in PluploadTest::testEvents from Oneup\UploaderBundle\Tests\Controller
    3x in FileBagExtractorTest::testWithMultipleFiles from Oneup\UploaderBundle\Tests\Controller

I wasn't able to make it work with iterators so using arrays with recursion instead: #448