feat: use Slice `id` property to key Slices in `<SliceZone>` when available

[lihbr]

Types of changes

• [ ] Chore (a non-breaking change which is related to package maintenance)
• [ ] Bug fix (a non-breaking change which fixes an issue)
• [x] New feature (a non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Description

Add support for Slice IDs, depends on https://github.com/prismicio/prismic-types/pull/45

Checklist:

• [ ] My change requires an update to the official documentation.
• [x] All TSDoc comments are up-to-date and new ones have been added where necessary.
• [x] All new and existing tests are passing.

[github-actions[bot]]

size-limit report 📦

Path	Size
dist/index.js	5.67 KB (+0.18% 🔺)
dist/index.cjs	7.3 KB (+1.59% 🔺)

[angeloashmore]

Looks good 👍

I left a comment in @prismicio/types about renaming slice_id to id (see comment). If we do that, we'll need to update the property here as well.