[apps.paint_annotations] Fix score bug and log warnings

[mmeendez8]

• [x] Paint scores only when predictions file is present
• [x] Warning "filename is not in ground truth file" appears even when filename is present in gt file
• [ ] Handle is_crowd attribute

[github-actions[bot]]

Branch bugfix/issue-107-_apps_paint_annotations_Fix_score_bug_and_log_warnings created!