Handle closed splines in Collada importer

(cherry picked from commit 8f7ab02bc637975a707455563f4954c2c43e976d)

editor/collada/collada.cpp

@@ -845,6 +845,8 @@ void Collada::_parse_curve_geometry(XMLParser &parser, String p_id, String p_nam
 
 	CurveData &curvedata = state.curve_data_map[p_id];
 	curvedata.name = p_name;
+	String closed = parser.get_attribute_value_safe("closed").to_lower();
+	curvedata.closed = closed == "true" || closed == "1";
 
 	COLLADA_PRINT("curve name: " + p_name);
 

editor/import/editor_import_collada.cpp

@@ -1074,6 +1074,12 @@ Error ColladaImport::_create_resources(Collada::Node *p_node, uint32_t p_use_com
 						c->set_point_tilt(i, tilts->array[i]);
 					}
 				}
+				if (cd.closed && pc > 1) {
+					Vector3 pos = c->get_point_position(0);
+					Vector3 in = c->get_point_in(0);
+					Vector3 out = c->get_point_out(0);
+					c->add_point(pos, in, out, -1);
+				}
 
 				curve_cache[ng->source] = c;
 				path->set_curve(c);