VIO 3.1 auto-crops uploaded reference images to 9:16 without warning, even when the original image is square

Bug description:
When using the VIO 3.1 model for video generation, uploading a reference image as the first frame causes the image to be automatically cropped to a 9:16 aspect ratio, even if the original image is square. The full reference image is not preserved, and there is no warning or option to adjust the crop.

Impact:
This unexpected cropping cuts important parts of the reference image, negatively affects the generated video, and resulted having a video being generated with an incorrect reference image.

Expected behavior:
The reference image should keep its original aspect ratio, or the user should be warned and allowed to confirm or adjust the crop before generation.