Update aiohttp requirement from ~=3.10.5 to ~=3.11.2 in /code/backend

Updates the requirements on [aiohttp](https://github.com/aio-libs/aiohttp) to permit the latest version.
- [Release notes](https://github.com/aio-libs/aiohttp/releases)
- [Changelog](https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst)
- [Commits](aio-libs/aiohttp@v3.10.5...v3.11.2)

---
updated-dependencies:
- dependency-name: aiohttp
  dependency-type: direct:production
...

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

code/backend/requirements.txt

@@ -1,6 +1,6 @@
 azure-identity~=1.17.1
 azure-monitor-opentelemetry~=1.6.2
-aiohttp~=3.10.5
+aiohttp~=3.11.2
 botbuilder-core~=4.16.2
 botbuilder-azure~=4.16.2
 botbuilder-integration-aiohttp~=4.16.2