fix(modem): Use virtual env for python packages

.github/workflows/modem__target-test.yml

@@ -80,7 +80,12 @@ jobs:
           name: modem_target_bin_${{ matrix.idf_target }}_${{ matrix.idf_ver }}_${{ matrix.test.app }}
           path: ${{ env.TEST_DIR }}/build
       - name: Run Example Test on target
-        working-directory: ${{ env.TEST_DIR }}
+        env:
+          PIP_EXTRA_INDEX_URL: "https://dl.espressif.com/pypi/"
         run: |
-            python -m pip install -r $GITHUB_WORKSPACE/ci/requirements.txt
+            python -m venv .venv
+            source .venv/bin/activate
+            pip install --prefer-binary cryptography pytest-embedded pytest-embedded-serial-esp pytest-embedded-idf pytest-custom_exit_code
+            pip install -r $GITHUB_WORKSPACE/ci/requirements.txt
+            cd ${{ env.TEST_DIR }}
             python -m pytest --log-cli-level DEBUG --target=${{ matrix.idf_target }}