Unused theme in `Theme.tsx`?

At a quick glance, deleting all content in this file (including the export) doesn't change the appearance nor does it break anything, and it does appear like the DLS theme being used comes from `sci-react-ui` rather than anything that is in tomohub's codebase: https://github.com/DiamondLightSource/TomoHub/blob/7f65ca72db6d4e98645d42a8a321bf1a81d6f23b/frontend/src/main.tsx#L12

so I'm inclined to think that this file isn't being used and thus could be removed.