Fix/missing return statement

[shota-0129]

Overview

This PR addresses the issue of a missing return statement in the function.

Changes

Added a return statement to the load_config() function

Reason for the Fix

It was discovered that a function was missing a return statement, leading to unexpected behavior. This PR adds the missing return statement to ensure the function operates correctly.

[wolny]

Hi @shota-0129, thanks for the fix!

[shota-0129]

@wolny
The AttributeError: 'csr_matrix' object has no attribute 'A' is occurring in the def _iou_matrix(gt, seg) function in pytorch3dunet\unet3d\seg_metrics.py, specifically on the line n_inter = contingency_table(gt, seg).A.
Referring to https://scikit-image.org/docs/stable/api/skimage.metrics.html#skimage.metrics.contingency_table, the return value is a scipy.sparse.csr_matrix, which doesn't have an 'A' attribute.
To resolve this, I substituted it with toarray().
This ended up being in the same PR, but is that okay?