chore: update Python tests workflow configuration

Author: Ki-Seki

.github/workflows/python-tests.yml

@@ -48,7 +48,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
         cache: 'poetry'
     - name: Ensure Poetry uses correct Python
-      run: poetry env use $(which python)
+      run: poetry env use python${{ matrix.python-version }}
 
     # Dependency and building tests
     - name: Install main dependencies