Fix: Filter out shared wall from collisions

CityDoctorParent/CityDoctorValidation/src/main/java/de/hft/stuttgart/citydoctor2/checks/topology/FeatureCollisionCheck.java

@@ -172,13 +172,17 @@ public class FeatureCollisionCheck extends Check{
                 .calculateGeometryIntersections(subjectGeom, candidateGeom, epsilon);
         return intersections.stream()
                         .filter( polySect -> polySect.getType() != PolygonIntersection.IntersectionType.NONE)
+                        .filter(polySect -> notCollinear(polySect.getT1(),polySect.getT2()))
                         .map(polySect -> new Pair<>(polySect.getP1(), polySect.getP2()))
                         .toList();
     }
 
+    private boolean notCollinear(Triangle3d t1, Triangle3d t2){
+        return !t1.getNormal().normalize().equalsWithEpsilon(t2.getNormal().normalize(), 0.01);
+    }
+
     private List<PolygonIntersection> getPolygonIntersections(Geometry subject, Geometry candidate){
         List<PolygonIntersection> intersections = new ArrayList<>();
-
         for(Polygon sPoly : subject.getPolygons()){
             for(Polygon cPoly : candidate.getPolygons()){
                 intersections.add(SelfIntersectionUtil.polygonIntersection(sPoly, cPoly, 0.001, epsilon));