Bump angular-split from 18.0.0 to 20.0.0 in /frontend (#653)

Bumps [angular-split](https://github.com/angular-split/angular-split) from 18.0.0 to 20.0.0.
- [Release notes](https://github.com/angular-split/angular-split/releases)
- [Changelog](https://github.com/angular-split/angular-split/blob/main/CHANGELOG.md)
- [Commits](angular-split/angular-split@v18.0.0...v20.0.0)

---
updated-dependencies:
- dependency-name: angular-split
  dependency-version: 20.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

frontend/package-lock.json

@@ -24,7 +24,7 @@
     "@angular/platform-browser-dynamic": "^18.2.14",
     "@angular/router": "^18.2.14",
     "@googlemaps/polyline-codec": "^1.0.28",
-    "angular-split": "^18.0.0",
+    "angular-split": "^20.0.0",
     "colors": "^1.4.0",
     "dotenv": "^17.2.3",
     "echarts": "^6.0.0",