[api] Bump pydantic from 2.11.5 to 2.11.7 in /backend

Bumps [pydantic](https://github.com/pydantic/pydantic) from 2.11.5 to 2.11.7.
- [Release notes](https://github.com/pydantic/pydantic/releases)
- [Changelog](https://github.com/pydantic/pydantic/blob/main/HISTORY.md)
- [Commits](pydantic/pydantic@v2.11.5...v2.11.7)

---
updated-dependencies:
- dependency-name: pydantic
  dependency-version: 2.11.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

backend/poetry.lock

@@ -16,7 +16,7 @@ python = "^3.12"
 litestar = {extras = ["prometheus"], version = "^2.16.0"}
 httpcore = "^1.0.9"
 gunicorn = "23.0.0"
-pydantic = "^2.11.5"
+pydantic = "^2.11.7"
 uvicorn = {extras = ["standard"], version = "^0.35.0"}
 tomli = "^2.2.1"