chore(deps): bump @rollup/rollup-linux-x64-gnu from 4.20.0 to 4.21.0 in /backend (#4003)

chore(deps): bump @rollup/rollup-linux-x64-gnu in /backend

Bumps [@rollup/rollup-linux-x64-gnu](https://github.com/rollup/rollup) from 4.20.0 to 4.21.0.
- [Release notes](https://github.com/rollup/rollup/releases)
- [Changelog](https://github.com/rollup/rollup/blob/master/CHANGELOG.md)
- [Commits](rollup/rollup@v4.20.0...v4.21.0)

---
updated-dependencies:
- dependency-name: "@rollup/rollup-linux-x64-gnu"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/package-lock.json

@@ -83,7 +83,7 @@
         "zod": "^3.23.8"
     },
     "optionalDependencies": {
-        "@rollup/rollup-linux-x64-gnu": "4.20.0"
+        "@rollup/rollup-linux-x64-gnu": "4.21.0"
     },
     "engines": {
         "node": ">=21.5.0"