Update entropy tutorial to use IEntropyV2 interface

- Add IEntropyV2.json ABI file to abis directory
- Update CoinFlip contract to use IEntropyV2 interface instead of IEntropy
- Fix constructor type declaration to use IEntropyV2
- Update description text to reference IEntropyV2 interface
- Ensure consistency across all interface references in the tutorial

Co-Authored-By: Jayant <[email protected]>

Author: devin-ai-integration[bot]