That old clay tile sewer pipe they used "back in the day" almost invites roots to breach it.... that crap was terible. The new line they put in should be impervious to roots from now to the end of time. It's highly unlikely the tree could breach the line again if they did it right. I'd think twice before taking it out unless you really want it to go. FWIW, A lot of the streets they have been redoing here in Duluth have trees between the curb of the street and the city sidewalk...it's not unusual.
Also FWIW, anyone in the market for a new home should have the sewer line inspected as part of the home inspection or as a contingency on the purchase agreement. We've purchased a number of homes lately and I've had to insist on seeing what the condition of the line is. Most home inspectors do not do this as a matter of course, and you will have to pay extra for it. Yet either way it's incredibly valuable info to have.... can save tons of money down the line or up front.
Several houses in my neighborhood recently had sewer problems. They tore out the whole driveway (covered sewer line) & floor of the garage and replaced with new cement. Not sure why they didn't cut and patch. City code? I've been curious about one case. The next door neighbor had a 2-3 foot diameter tree planted a couple of feet from the property line. They cut the tree down at the same time, just wondered whose insurance covered the damages.