Dealer says that noise is brake actuator

You could get a used unit on eBay and have a local mechanic install it if you can’t do that yourself. No guarantee the used unit will work though. Dorman sells remanufactured units for about 800.

 

welcome!
you don't need to replace it until it fails, and it may never fail

 

On my 2006 the brake actuator was noisy sometimes but not that bad as the video. I changed the brake fluid which costs less than $15 for 2 quarts using techstream and it is much quieter the past 15k miles.

 

Your ABS actuator might be faulty but you can only tell for certain if there are warning lights on the dash and when diagnosed, the following codes appear: C1253,C1256,C1311,C1313.

There are 4 Gen2 Priuses in the family and all of them produce this sound but an ABS actuator was needed replacement on only one.

I would leave it alone until it produces error codes and do a dealership brake fluid change - can only be done using Toyota diagnostics tool - Techstream. Bleeding the brakes in general won't be ok. Often what kills the ABS actuator is the not frequent brake fluid change. These are the warning lights I had on when the ABS actuator went on mine: