To be fair, the question asked is specifically... "Do suspension forks improve safety on Urban ebikes?"
I'd agree with
@Mr. Coffee that in URBAN environments, they really don't do much in the way of safety, unless you frequently hop curbs, or live in a city with really lousy infrastructure and/or a lot of street car tracks. In those cases, 2" or wider tires will do just as much for safety as a fork.
In my personal experience of 30+ years of cycling in the city, the difference between a suspension and no suspension is negligible. Having 2" tires (sewer grates, streetcar tracks) is WAY more important. You don't want to have to avoid a car door doing 20+mph only to have your skinny tires hit the edge of the tracks.
One of my ribs has been an excellent predictor of rain for about 25 years, thanks to 28mm tires.