Bump @mantine/form from 6.0.21 to 7.7.0 in /src/frontend (#6879)

Bumps [@mantine/form](https://github.com/mantinedev/mantine/tree/HEAD/packages/@mantine/form) from 6.0.21 to 7.7.0.
- [Release notes](https://github.com/mantinedev/mantine/releases)
- [Changelog](https://github.com/mantinedev/mantine/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mantinedev/mantine/commits/7.7.0/packages/@mantine/form)

---
updated-dependencies:
- dependency-name: "@mantine/form"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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src/frontend/package.json

@@ -23,7 +23,7 @@
         "@mantine/core": "<7",
         "@mantine/dates": "<7",
         "@mantine/dropzone": "<7",
-        "@mantine/form": "<7",
+        "@mantine/form": "<8",
         "@mantine/hooks": "<7",
         "@mantine/modals": "<7",
         "@mantine/notifications": "<7",