fix: validate tensor shapes in get_stats for multiclass mode#1284

lapertor wants to merge 3 commits intoqubvel-org:mainqubvel-org/segmentation_models.pytorch:mainfrom

lapertor:fix/get-stats-multiclass-shape-validationlapertor/segmentation_models.pytorch:fix/get-stats-multiclass-shape-validationCopy head branch name to clipboard