DOT4-GRAVITY - Logic adjustment

[DidacSF]

Description

Changed the end game logic in ajuna-board pallet, now when a game finishes the board is not removed from storage, only the player references to it.

A new extrinsic clear_board has been added to remove the boards. The change comes from the need of being able to check previously completed games.

Type of changes

• [ ] build: Changes that affect the build system or external dependencies (eg, Cargo, Docker)
• [ ] ci: Changes to CI configuration
• [ ] docs: Changes to documentation only
• [x] feat: Changes to add a new feature
• [ ] fix: Changes to fix a bug
• [ ] refactor: Changes that do not alter functionality
• [ ] style: Changes to format the code
• [x] test: Changes to add missing tests or correct existing tests

Checklist

• [x] Tests for the changes have been added
• [x] Necessary documentation is added (if appropriate)
• [x] Formatted with cargo fmt --all
• [x] Linted with cargo clippy --all-features --all-targets
• [x] Tested with cargo test --workspace --all-features --all-targets