Kia Niro 2020 PHEV EX Premium supports longitudinal control and steering to 0 MPH

### Describe the bug or enhancement

These flags are specific to the trim of the car, and the flags set for this model do not reflect that. In particular, I've tested on my Kia Niro PHEV 2020 EX Premium, and I removed these flags and confirmed that the vehicle does have longitudinal control and can steer all the way to 0 MPH. These flags can be removed from the configuration safely.
```
HyundaiFlags.UNSUPPORTED_LONGITUDINAL | HyundaiFlags.MIN_STEER_32_MPH
```
The code that should be modified is here
https://github.com/commaai/opendbc/blob/a80f6f74f62b7aed6a02b35ec7c61a6a62d14873/opendbc/car/hyundai/values.py#L436

I do not understand this codebase enough to add a trim-specific version of this car. I think some of the more basic trims would not support steering to 0 MPH, so that should be kept as an option.

### Provide a route where the issue occurs if applicable

_No response_

### openpilot version if applicable

_No response_

### Additional info

_No response_