add VehicleConsumer mock (#359)

src/components/Contexts/__mocks__/VehicleContext.jsx

@@ -92,6 +92,10 @@ export const VehicleProvider = ({ children }) => {
   return <div data-testid="mocked-vehicleprovider">{children}</div>;
 };
 
+export const VehicleConsumer = ({ children }) => {
+  return children();
+};
+
 export const useVehicleContext = () => ({
   busy,
   models,