Update pydantic-settings requirement in /code/function

Updates the requirements on [pydantic-settings](https://github.com/pydantic/pydantic-settings) to permit the latest version.
- [Release notes](https://github.com/pydantic/pydantic-settings/releases)
- [Commits](pydantic/pydantic-settings@v2.5.2...v2.6.0)

---
updated-dependencies:
- dependency-name: pydantic-settings
  dependency-type: direct:production
...

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

Author: dependabot[bot]

code/function/requirements.txt

@@ -5,7 +5,7 @@
 # azure-identity~=1.15.0
 azure-functions~=1.21.1
 fastapi~=0.115.0
-pydantic-settings~=2.5.2
+pydantic-settings~=2.6.0
 httpx~=0.27.2
 azure-monitor-opentelemetry-exporter==1.0.0b30
 opentelemetry-instrumentation-fastapi==0.48b0