A shutter sound would only come from an analog camera. If you heard a shutter sound from a smart TV, then it is coming from the speakers. The light also does not indicate that a camera is in use. The only way to be sure that a particular smart tv did not have a camera is to disassemble it. Short of that, shine a strong light around the bezel looking for a pin hole or a one-way filter.
If you want to secure your smart tv today, use a filter such as a Pi-Hole. I find my TV trying to talk to Roku all the time, and depending on the app other services. You could always break the functionality of the smart TV by setting an unroutable IP address, but that would defeat the whole point of using a smart TV.