MarkerLayer: tell type system that all features have IDs

[singingwolfboy]

This fixes some Typescript warnings, and improves type safety in general.

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 66d9e53a5dc38b7238940f94f4c913df93992667

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | --------------- | ----- | | svelte-maplibre | Patch |

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[dimfeld]

Thanks! I’ll put out a new release later tonight.