Bump axios and @sap/approuter in /app

Bumps [axios](https://github.com/axios/axios) to 1.15.2 and updates ancestor dependency @sap/approuter. These dependencies need to be updated together.


Updates `axios` from 1.15.0 to 1.15.2
- [Release notes](https://github.com/axios/axios/releases)
- [Changelog](https://github.com/axios/axios/blob/v1.x/CHANGELOG.md)
- [Commits](axios/axios@v1.15.0...v1.15.2)

Updates `@sap/approuter` from 21.3.0 to 21.4.0

---
updated-dependencies:
- dependency-name: axios
  dependency-version: 1.15.2
  dependency-type: indirect
- dependency-name: "@sap/approuter"
  dependency-version: 21.4.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]