The above-the-line deduction for attorney fees is only for claims of unlawful discrimination. If that is not the basis for your claim, you cannot take the above-the-line deduction.
There is no way to enter the above-the-line deduction for attorney fees for an unlawful discrimination claim in TurboTax Online. It can only be entered in forms mode, which is available only in the CD/Download TurboTax software, not in TurboTax Online. Officially the deduction is not supported in TurboTax at all. It was added to the list of unsupported calculations for 2018. However, it can still be entered in forms mode in TurboTax for 2018. It's too soon to know whether it will still be possible to enter it for 2019.