Geometry Nodes: Set Handle Type Node: Left and right by default

This node's UI uses a multi-select enum to allow adjusting the
type of both handle sides with the same node. Since usually the
user wants to affect both handles, and it's the multi-select behavior
isn't obvious, selecting both by default is an improvement.

source/blender/nodes/geometry/nodes/node_geo_curve_set_handles.cc

@@ -43,7 +43,7 @@ static void node_init(bNodeTree *UNUSED(tree), bNode *node)
   NodeGeometryCurveSetHandles *data = MEM_cnew<NodeGeometryCurveSetHandles>(__func__);
 
   data->handle_type = GEO_NODE_CURVE_HANDLE_AUTO;
-  data->mode = GEO_NODE_CURVE_HANDLE_LEFT;
+  data->mode = GEO_NODE_CURVE_HANDLE_LEFT | GEO_NODE_CURVE_HANDLE_RIGHT;
   node->storage = data;
 }