build(deps-dev): bump @smui/textfield in /frontend (#1013)

Bumps [@smui/textfield](https://github.com/hperrin/svelte-material-ui) from 7.0.0-beta.8 to 7.0.0-beta.15.
- [Changelog](https://github.com/hperrin/svelte-material-ui/blob/master/CHANGELOG.md)
- [Commits](hperrin/svelte-material-ui@v7.0.0-beta.8...v7.0.0-beta.15)

---
updated-dependencies:
- dependency-name: "@smui/textfield"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

frontend/package.json

@@ -29,7 +29,7 @@
         "@smui/segmented-button": "^7.0.0-beta.9",
         "@smui/select": "7.0.0-beta.8",
         "@smui/slider": "^7.0.0-beta.14",
-        "@smui/textfield": "7.0.0-beta.8",
+        "@smui/textfield": "7.0.0-beta.15",
         "@svelte-plugins/tooltips": "^0.1.6",
         "@sveltejs/vite-plugin-svelte": "1.4.0",
         "@testing-library/jest-dom": "^5.16.5",