build(deps-dev): bump svelte-preprocess from 5.1.4 to 6.0.3

Bumps [svelte-preprocess](https://github.com/sveltejs/svelte-preprocess) from 5.1.4 to 6.0.3.
- [Changelog](https://github.com/sveltejs/svelte-preprocess/blob/main/CHANGELOG.md)
- [Commits](sveltejs/svelte-preprocess@v5.1.4...v6.0.3)

---
updated-dependencies:
- dependency-name: svelte-preprocess
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -88,7 +88,7 @@
     "sirv-cli": "^2.0.2",
     "svelte": "^3.59.2",
     "svelte-check": "^3.8.6",
-    "svelte-preprocess": "^5.1.3",
+    "svelte-preprocess": "^6.0.3",
     "sveltestrap": "^5.11.3",
     "tslib": "^2.7.0",
     "typescript": "^5.5"