feat(test): Enhance GroupingIntegration test robustness and documentation

[SashaMalysehko]

Description

This PR enhances the GroupingIntegration test suite with improved reliability, documentation, and error handling. Changes include:

• Add comprehensive NatSpec documentation for all test functions
• Implement robust error handling with descriptive messages
• Convert mutable numIps to immutable NUM_IPS constant
• Add overflow protection for fee calculations
• Implement validation checks for multicall operations
• Improve code readability and maintainability

Test Plan

1. Run the complete test suite:

2. Verify all test cases pass:

• Minting and registering IP with license
• Group registration and license attachment
• Batch operations via multicall
• Royalty collection and distribution
• Error cases with invalid inputs

3. Check error handling:

• Zero address validations
• Uninitialized contract states
• Invalid signature generations
• Overflow conditions in fee calculations

Related Issue

Relates to improving test suite reliability and maintainability
Issue #[Add relevant issue number]

Notes

• All existing functionality remains unchanged
• Added validations may cause tests to fail if preconditions aren't met
• Documentation follows Solidity NatSpec standard
• Error messages are standardized and descriptive

[sebsadface]

Thank you for your contribution! I noticed that some of the checks you’ve added appear to be redundant. Please review the comments and make changes accordingly.

[SashaMalysehko]

@sebsadface Thank you too. I corrected the code