Sims 4 certainly has not been hacked.
As long as you downloaded and installed "The Sims 4 Cas Demo" via the official Origin Client, available on the official site here, there should be no reason for your security software to trigger any alerts.
If it does anyway, please get in touch with the manufacturer of your security software, and ask them to review why these alerts were triggered. There might be an unrelated issue with other files on your computer that they might be able to help you with.
Additionally, I would also like to encourage you to run a deep scan on your computer.