[UF - Screenshots] Allow rectangle marked as 'screenshotted element' to be draggable

[jas-kas]

I would love to be able to move this rectangle for e.g.:

[c298lee]

This will currently take quite a bit of effort to implement because of how cropping is currently done. Once we implement select and deselect for annotations, we could also implement this too since the behaviour is the same.

[AbhiPrasad]

sorry for driveby - was cleaning up some issues, but I think this is done with #13071

released with https://github.com/getsentry/sentry-javascript/releases/tag/8.21.0