UI issues discovered while testing the tailwind version bump

Placeholder issue for issues found while testing the [tailwind version bump](https://github.com/FlowFuse/flowfuse/pull/7203) pr.

Many of them were pre-existing but were uncovered when sweeping the app for the tailwind bump.

A few patterns worth noting if you want to bundle work:

- Loader centering comes up across many pages could be a single sweep task instead of nine
- Scrolling fixes for tables/search bars are also a recurring pattern, might be worth a shared layout component or pattern fix