Empty state has black text for theme example in light mode

[BluePandaCard]

Summary of the bug

When working on #1274 I noticed that empty state works fine in dark mode for the theme example, but in light mode it looks like this:

It has theme="dark" so it should appear with white text.

I checked the ui kit repo and it works fine there so not sure what the issue might be here.

🧐 Expected behaviour

Should be able to see the text in both light and dark mode.

[ad9242]

it looks like the theme prop has not been added to the EmptyState component in the ui-kit.

work from mi6/ic-ui-kit#2513 seems to have been lost