The IRS does not start processing tax returns until at least February 12, so we don’t know yet how they will be handling the situation, although it is expected to be fairly common. There are at least three possibilities I can think of.
1. The IRS will reject your tax return, you will be able to remove the payment before you re-transmit it.
2. The IRS will remove the payment from your refund automatically. The law gives them the authority to treat this situation as a mathematical mistake, meaning they can fix it on their own without sending you a letter or requiring you to amend. We don’t know yet if they will actually do this, and if they do, I expect it will delay your refund payment because your tax return will have to be kicked out of the normal automatic system and handled by a person.
3. The IRS could pay the full amount of your claimed refund and then send you a bill later for the excess payment. If you do happen to get the full payment, don’t spend it all, and set aside the excess payment because the IRS will probably ask for it back.
TurboTax has established a procedure for taxpayers in your situation. Please see the TurboTax Help article I've already claimed the Recovery Rebate Credit. How can I review and update my 2020 tax return? for guidance.