build(deps): bump vuex from 3.6.2 to 4.1.0 in /build/frontend-legacy

Bumps [vuex](https://github.com/vuejs/vuex) from 3.6.2 to 4.1.0.
- [Release notes](https://github.com/vuejs/vuex/releases)
- [Changelog](https://github.com/vuejs/vuex/blob/main/CHANGELOG.md)
- [Commits](vuejs/vuex@v3.6.2...v4.1.0)

---
updated-dependencies:
- dependency-name: vuex
  dependency-version: 4.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

build/frontend-legacy/package-lock.json

@@ -98,7 +98,7 @@
     "vue-material-design-icons": "^5.3.1",
     "vue-router": "^3.6.5",
     "vuedraggable": "^2.24.3",
-    "vuex": "^3.6.2",
+    "vuex": "^4.1.0",
     "vuex-router-sync": "^5.0.0",
     "webdav": "^5.8.0"
   },