create_shape - raise the same error for representations and rep items

To be consistent with how it's handled when product+representation is passed, previously it would fail silently.

src/ifcgeom/Converter.cpp

@@ -389,7 +389,9 @@ IfcGeom::ConversionResults ifcopenshell::geometry::Converter::convert(IfcUtil::I
 	IfcGeom::ConversionResults results;
 	if (geom_item) {
 		std::clock_t geom_start = std::clock();
-		kernel_->convert(geom_item, results);
+		if (!kernel_->convert(geom_item, results)) {
+			throw std::runtime_error("Failed to convert item");
+		}
 		std::clock_t geom_end = std::clock();
 		total_map_time += (geom_start - map_start) / (double) CLOCKS_PER_SEC;
 		total_geom_time += (geom_end - geom_start) / (double) CLOCKS_PER_SEC;

src/ifcwrap/IfcGeomWrapper.i

@@ -844,7 +844,12 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
 					// https://github.com/IfcOpenShell/IfcOpenShell/issues/1649
 					instance->declaration().is(Schema::IfcProfileDef::Class())
 				) {
-					IfcGeom::ConversionResults shapes = kernel.convert(instance);
+					IfcGeom::ConversionResults shapes;
+					try {
+						shapes = kernel.convert(instance);
+					} catch (...) {
+						throw IfcParse::IfcException("Failed to process shape");
+					}
 
 					IfcGeom::Representation::BRep brep(settings, instance->declaration().name(), to_locale_invariant_string(instance->data().id()), shapes);
 					try {