When you visit a segment page, you can click either endpoint of the segment to be brought to the street view for that location. You can also select one of the options from the map view menu (pictured below).
Since Strava's switch off Google Maps: Our new maps by Mapbox do not provide street view functionality at this time. We’ve heard that Google Street View is important to a small but passionate group of athletes and we are working on making Google Street View accessible at key touchpoints in the Strava experience. Street view is currently available when creating segments and for visualization at the start and end of segments.