flipped normals for gambrel walls

[Bauer33333]

The normals on the gable walls of gambrel roofs are inverted. Also the windows on them are not visible, but maybe this is caused by the normals.

Screenshots

**Location https://streets.gl/#48.80809,9.58164,44.25,328.75,100.20

System information

• OS: Windows 10
• Browser with version: Firefox 115.0.2