Bump styled-components from 6.1.8 to 6.1.15 in /frontend

Bumps [styled-components](https://github.com/styled-components/styled-components) from 6.1.8 to 6.1.15.
- [Release notes](https://github.com/styled-components/styled-components/releases)
- [Commits](https://github.com/styled-components/styled-components/compare/[email protected])

---
updated-dependencies:
- dependency-name: styled-components
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

frontend/package.json

@@ -31,7 +31,7 @@
     "react-multi-select-component": "4.3.4",
     "react-router-dom": "6.23.0",
     "sass": "1.66.1",
-    "styled-components": "6.1.8",
+    "styled-components": "6.1.15",
     "use-debounce": "10.0.0",
     "yup": "1.4.0",
     "zustand": "4.5.2"