Support drag and drop in event highlights fields

### Problem Statement You just shipped customisable "event highlights", which are great. However you can only add/remove event highlights from the list, and are unable to re-order them how you want. <img width="807" alt="SCR-20240503-lppb" src="https://github.com/getsentry/sentry/assets/29406849/56398799-96d5-4b9d-a54c-493e117d300f"> In the example above, if I wanted to move "organisation_id" to be after "User", I'd have to remove it and then add it again. It gets a bit complicated if you add loads of fields. ### Solution Brainstorm Support dragging and dropping the fields ### Product Area Issues