fix(json-abi): Param.ty is not always a valid TypeSpecifier

[DaniPopes]

Closes foundry-rs/foundry#6113

The exact same code, with library instead of contract, produces "type": "Library.Enum" instead of "uint8".

See also ethabi workaround: https://github.com/rust-ethereum/ethabi/blob/b1710adc18f5b771d2d2519c87248b1ba9430778/ethabi/src/param_type/reader.rs#L162-L167

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract ContractCounter {
    enum TestEnum {
        NO,
        YES
    }

    function sayYes() external pure returns (TestEnum) {
        return TestEnum.YES;
    }
}

library LibCounter {
    enum TestEnum {
        NO,
        YES
    }

    function sayYes() external pure returns (TestEnum) {
        return TestEnum.YES;
    }
}