Add 400 Gbps speed

### NetBox version

v4.0.6

### Feature type

Data model extension

### Proposed functionality

Add 400 Gbps speed to `circuits.Circuit.commit_rate` and `circuits.CircuitTermination.port_speed` choices

### Use case

QOL feature, as 400 Gbps is becoming standard 

### Database changes

_No response_

### External dependencies

_No response_