Service areas aren't treated as areas

[MMK21Hub]

When quests are shown on a highway=services, the outline is treated as a line, instead of treating it as an area. This is inconsistent with, for example, buildings or playgrounds.

How to Reproduce

1. Use Overpass Turbo to find service areas near you
2. Find a service area in StreetComplete that has a quest (e.g. Are there any toilets here?)
3. Tap on the quest

Expected Behavior

The quest pin appears in the middle of the area, and the area is highlighted when tapping on the quest

Versions affected

StreetComplete v51.0 and v50.2 (older versions not tested)

Screenshot

[matkoniecz]

Thanks!