imagedestroy() is deprecated since PHP 8.5, as it has no effect since PHP 8.0

[A-smart-kitten]

As far as I can see, Thumbnail.php currently includes two calls to the PHP function imagedestroy:

MW-Avatar/Thumbnail.php

Lines 32 to 36 in e7974e8

	public function cleanup() {
	imagedestroy($this->image);
	$this->image = null;
	}

MW-Avatar/Thumbnail.php

Lines 51 to 53 in e7974e8

	imagedestroy($thumb);
	}

This function is deprecated since PHP 8.5, as it has no effect since PHP 8.0.

[Cross-reference https://phabricator.wikimedia.org/T413901]