Update ser tests_path for windows

Author: vlad-perevezentsev

.github/workflows/conda-package.yml

@@ -418,7 +418,7 @@ jobs:
 
       - name: Set tests_path for installed package
         run: |
-          FOR /F "delims=" %i IN ('python -c "import site, os; print(os.path.join(site.getsitepackages()[0], 'dpnp', 'tests'))"') DO SET tests_path=%i
+          FOR /F "delims=" %%i IN ('python -c "import site, os; print(os.path.join(site.getsitepackages()[0], 'dpnp', 'tests'))"') DO SET tests_path=%%i
           echo tests_path=%tests_path%>>%GITHUB_ENV%
 
       - name: Run tests