build(deps-dev): bump responses from 0.25.7 to 0.25.8 in /backend (#2756)

Bumps [responses](https://github.com/getsentry/responses) from 0.25.7 to 0.25.8.
- [Release notes](https://github.com/getsentry/responses/releases)
- [Changelog](https://github.com/getsentry/responses/blob/master/CHANGES)
- [Commits](getsentry/responses@0.25.7...0.25.8)

---
updated-dependencies:
- dependency-name: responses
  dependency-version: 0.25.8
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

backend/requirements-dev.txt

@@ -2,4 +2,4 @@ fakeredis==2.33.0
 pre-commit==4.5.1
 pytest==9.0.2
 pytest-responses==0.5.1
-responses==0.25.7
+responses==0.25.8