test: fuzzing utils and csv_parser

[yagnadeepxo]

Test Summary

During Fuzz tests, The assertion is failing when comparing an empty string's bytes ([]) to the result of converting that empty string to a BigUint and then back to bytes, which results in [0]. it's happening because when we convert an empty string to a BigUint using BigUint::from(0u8), it's equivalent to a BigUint representing the number 0, which, when converted back to bytes, gives [0] instead of an empty array.

To fix this issue, we need to ensure that converting an empty string to a BigUint and back maintains consistency with the original input.