fix: add bigint replacer to maths json stringify

[Aerilym]

This pull request introduces a utility function for JSON stringification with BigInt support and integrates it into existing error handling in the apps/staking/tests/maths.spec.ts file. The changes improve the handling of BigInt values during debugging and error reporting.

Utility Function Addition:

• Added jsonBigIntReplacer import from @session/util-js/bigint.
• Introduced a jsonStringify helper function that uses JSON.stringify with jsonBigIntReplacer to handle BigInt values.

Error Handling Improvement:

• Updated error message in the parseContributorDetails fuzzing test to use jsonStringify for better representation of BigInt values in the contributors object.

[Copilot]

Pull Request Overview

This PR improves BigInt handling in error reporting for the maths module by introducing a JSON stringification helper that uses a custom BigInt replacer.

• Imported jsonBigIntReplacer to handle BigInt values.
• Introduced jsonStringify helper for improved error message formatting.
• Integrated jsonStringify in the error handling within the parseContributorDetails fuzzing test.

[Copilot]

[nitpick] Consider adding a brief comment explaining the purpose of the jsonStringify helper and its relation to handling BigInt values, to improve code maintainability and clarity.

[Copilot]

[nitpick] Verify that the enhanced error message provides sufficient context for debugging; consider logging additional relevant details if future debugging proves challenging.

Suggested change

	throw new Error(`Failed to get min stake for ${jsonStringify(contributors)} ${e}`);
	throw new Error(
	`Failed to get min stake during fuzz test iteration ${i}/${fuzzAmount}. ` +
	`Contributors: ${jsonStringify(contributors)}. ` +
	`Error: ${e}. ` +
	`State: { minStake: ${minStake ?? 'undefined'}, totalStaked: ${totalStaked ?? 'undefined'} }`
	);