Height limit quest should be disabled on railroad crossings with private access

**How to Reproduce** Scan for max height quests around a railway crossing on a private road, like https://www.openstreetmap.org/node/12055466516 or https://www.openstreetmap.org/node/12060315666, and StreetComplete will generate the "What height limit is indicated here?" quest. **Expected Behavior** No such quests should appear, because the quests are on a private road and not accessible. **Versions affected** SCEE v63.1 and SC v63.1 on Android 16