refactor: update data structure in app.py and text_to_image.jsonl to replace 'Provider' with 'Platform' and 'Owner', enhancing clarity and consistency in data representation

chore: update text-to-image data entries to reflect new provider names and device specifications, standardizing optimization labels to 'Undisclosed' for clarity

feat: implement text-to-image leaderboard in app.py, updating data source and enhancing user interface with new tab and detailed performance metrics for various providers