Bump @sap/cds-dk from 7.9.4 to 8.8.0 in /samples/cds-sample-application

Bumps [@sap/cds-dk](https://cap.cloud.sap/) from 7.9.4 to 8.8.0.

---
updated-dependencies:
- dependency-name: "@sap/cds-dk"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]