Bump newsroom-core from 320e90b to ff2815d in /client (#220)

Bumps [newsroom-core](https://github.com/superdesk/newsroom-core) from `320e90b` to `ff2815d`.
- [Release notes](https://github.com/superdesk/newsroom-core/releases)
- [Commits](superdesk/newsroom-core@320e90b...ff2815d)

---
updated-dependencies:
- dependency-name: newsroom-core
  dependency-type: direct:production
...

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