feat: add option for finnish

[j0h-dev]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Add finnish keyboard layout as an option for UX reasons
  • Uses the same layout XML as the swedish keyboard due to them being the same layout (in most keyboard apps)

Tests performed

• Tested on a Pixel 10 Pro running GrapheneOS

Closes the following issue(s)

• Closes Add a finnish keyboard layout #437

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• I understand every change in this pull request.