feat: update devcontainer to Python 3.14, remove 3.9 image reference

Agent-Logs-Url: https://github.com/microsoftgraph/msgraph-sdk-python-core/sessions/f8b5c8c9-e430-42e8-8fe2-42673c863a3e

Co-authored-by: ramsessanchez <63934382+ramsessanchez@users.noreply.github.com>

Author: Copilot

.devcontainer/devcontainer.json

@@ -3,13 +3,12 @@
 {
   "name": "Python 3",
   // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
-  // "image": "mcr.microsoft.com/devcontainers/python:3.9-bookworm",
   // "image": "mcr.microsoft.com/devcontainers/python:3.10-bookworm",
   // "image": "mcr.microsoft.com/devcontainers/python:3.11-bookworm",
   // "image": "mcr.microsoft.com/devcontainers/python:3.12-bookworm",
   // "image": "mcr.microsoft.com/devcontainers/python:1-3.12-bullseye",
   // "image": "mcr.microsoft.com/devcontainers/python:3.13-bookworm",
-  "image": "mcr.microsoft.com/devcontainers/python:3.13-bullseye",
+  "image": "mcr.microsoft.com/devcontainers/python:3.14-bookworm",
 
   "features": {
     "ghcr.io/hspaans/devcontainer-features/pytest:1": {},