Bump fastapi from 0.115.5 to 0.115.6

Bumps [fastapi](https://github.com/fastapi/fastapi) from 0.115.5 to 0.115.6.
- [Release notes](https://github.com/fastapi/fastapi/releases)
- [Commits](fastapi/fastapi@0.115.5...0.115.6)

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

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

Author: dependabot[bot]

src/backend/requirements.txt

@@ -65,7 +65,7 @@ environs==11.2.1
     # via fastapi-app (pyproject.toml)
 exceptiongroup==1.2.2
     # via anyio
-fastapi==0.115.5
+fastapi==0.115.6
     # via fastapi-app (pyproject.toml)
 fixedint==0.1.6
     # via azure-monitor-opentelemetry-exporter