Bump tar from 4.4.15 to 4.4.19 in /backend

Bumps [tar](https://github.com/npm/node-tar) from 4.4.15 to 4.4.19.
- [Release notes](https://github.com/npm/node-tar/releases)
- [Changelog](https://github.com/npm/node-tar/blob/main/CHANGELOG.md)
- [Commits](isaacs/node-tar@v4.4.15...v4.4.19)

---
updated-dependencies:
- dependency-name: tar
  dependency-type: indirect
...

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

Author: dependabot[bot]