add test for input_boxes

[sabman]

The model should in theory support input_boxes as per this issue: https://huggingface.co/Xenova/slimsam-77-uniform/discussions/2#65c022977c6ad1994b893a8d but there's not test or example to verify this. I also couldn't get the model to accept the input_boxes on the main branch. Getting error:

Error: An error occurred during model execution: "Missing the following inputs: input_points, input_labels.

[mhassanch]

I checked optimum package and it seems that input_boxes is missing as input in SamOnnxConfig https://github.com/huggingface/optimum/blob/adcae3841ac638aa911e6a185d3f1617e58495f8/optimum/exporters/onnx/model_configs.py#L2408

Also there is no test available with input_boxes as a input in transformer.js https://github.com/huggingface/transformers.js/blob/1130961ac26766ba4a0f5af2640925f4f39b9974/tests/models/sam/test_modeling_sam.js

But it can be seen that SamImageProcessor is using input_boxes to process image.

transformers.js/src/models/sam/image_processing_sam.js

Line 142 in 1130961

if (input_boxes) {