Tiled Gallery block: Hide 'Link To' options if Carousel is enabled

### Suggestion

If Carousel is enabled, then by default none of the 'Link To' options for Tiled Gallery block images will work, the Carousel taking precedence.

It may make more sense to hide these 'Link To' options when Carousel is enabled, perhaps adding a link to enable / disable Carousel, along with an explanation of why these options aren't showing.

However for custom links in particular (newly added here - https://github.com/Automattic/jetpack/pull/41471), it may make more sense for the images within Carousel's to include the custom links as well (see issue https://github.com/Automattic/jetpack/issues/42096), in which case showing the custom link option would still make sense.

Mentioned in internal testing: p8oabR-1Di-p2#comment-8406

Start with the Tiled Gallery block's Carousel and “Link To” controls, then review PR #41471 and issue #42096 for the custom-link context. The issue needs a settled choice between hiding the options or carrying custom links into the Carousel; done means the selected behavior is implemented and explained consistently.

Written by the indexing model from the issue text.