Tests: Fix deprecation warning

dune/solvers/test/common.hh

@@ -294,7 +294,7 @@ void assemblePQ1RHS(const GridView& gridView, Vector& r, const Function& f)
 template<class Intersection>
 bool intersectionContainsVertex(const Intersection& i, int vertexInInsideElement)
 {
-    static const int dim = Intersection::dimension;
+    static const int dim = Intersection::Entity::dimension;
 
     int faceIdx = i.indexInInside();