getObjectContents() doesn't return file content for binary files

[Mark-H]

https://github.com/modxcms/aws-s3-media-source/blob/master/core/components/awss3mediasource/model/awss3mediasource/awss3mediasource.class.php#L1491

Example is when using this media source with MoreGallery; that will use getObjectContents() to load the image to create thumbnails/crops, however that wont work because images are binary files.

I'm not quite sure why the check on binary files is there to begin with, and have confirmed it works fine when replacing the ternary with just $contents.