build: bump httpx from 0.28.0 to 0.28.1 in /App

Bumps [httpx](https://github.com/encode/httpx) from 0.28.0 to 0.28.1.
- [Release notes](https://github.com/encode/httpx/releases)
- [Changelog](https://github.com/encode/httpx/blob/master/CHANGELOG.md)
- [Commits](encode/httpx@0.28.0...0.28.1)

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

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

Author: dependabot[bot]

App/requirements.txt

@@ -16,4 +16,4 @@ azure-identity
 azure-mgmt-resource
 aiohttp
 fastapi==0.115.6
-httpx==0.28.0
+httpx==0.28.1