[Python] Restore required dev dependency + Adjust generated Github workflow (#19773)

* Restore required python client dev dependency pytest-cov

* Harmonize python client workflow definitions

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Co-authored-by: Pascal Bachor <bachorp@users.noreply.github.com>

samples/client/echo_api/python/.github/workflows/python.yml

@@ -24,15 +24,8 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install flake8 pytest
-          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-          if [ -f test-requirements.txt ]; then pip install -r test-requirements.txt; fi
-      - name: Lint with flake8
-        run: |
-          # stop the build if there are Python syntax errors or undefined names
-          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
-          # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-          flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+          pip install -r requirements.txt
+          pip install -r test-requirements.txt
       - name: Test with pytest
         run: |
-          pytest
+          pytest --cov={{packageName}}