Remove Python 3.9 (EOL) and update to latest Python versions

Python 3.9 reached end-of-life in October 2025. Remove it from
workspace images to align with Python's support lifecycle and
allow using latest Poetry (2.3.0+) which dropped Python 3.9 support.

Co-authored-by: Ona <no-reply@ona.com>

Author: kylos101

chunks/lang-python/chunk.yaml

@@ -11,6 +11,3 @@ variants:
   - name: "3.10"
     args:
       PYTHON_VERSION: 3.10.19
-  - name: "3.9"
-    args:
-      PYTHON_VERSION: 3.9.25