Menu has wrong data-test attribute

See [here](https://github.com/dhis2/ui/blob/master/packages/core/src/Menu/Menu.js#L47):

<img width="367" alt="Screenshot 2020-06-22 at 11 37 37" src="https://user-images.githubusercontent.com/7355199/85272692-d0c90200-b47c-11ea-9e2c-0463d5788e34.png">
