fix convert ansi pluign

Author: SimenB

packages/pretty-format/src/ConvertAnsi.ts

@@ -5,6 +5,4 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import ConvertAnsi from './plugins/ConvertAnsi';
-
-export default ConvertAnsi;
+export {test, serialize} from './plugins/ConvertAnsi';