chore: Update lint workflow to use poetry for running Mypy (#3630)

Update lint workflow to run Mypy directly with poetry

.github/workflows/lint-py.yml

@@ -38,6 +38,6 @@ jobs:
           poetry install
       - name: Run Mypy
         run: |
-          make lint
+          poetry run mypy --namespace-packages -p "langflow"
         env:
           GITHUB_TOKEN: ${{ secrets.github_token }}