Update azure-functions requirement in /code/function

---
updated-dependencies:
- dependency-name: azure-functions
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

code/function/requirements.txt

@@ -3,7 +3,7 @@
 # Manually managing azure-functions-worker may cause unexpected issues
 
 # azure-identity~=1.15.0
-azure-functions~=1.21.0
+azure-functions~=1.21.1
 fastapi~=0.115.0
 pydantic-settings~=2.5.2
 httpx~=0.27.2