You should be able to see the effects of pedal lines by way of the grey line that shows the automatic data that is generated by Dorico when it is setting things up for playback. Set up a MIDI CC editor to point at CC64. It can be difficult to see the lines because of course the value is either 0 or 127, but you should be able to see the vertical lines that appear at the transitions between the pedal being depressed and lifted.