Properly stop driver before nullifying

As suggested by the review bot

Author: lauromoura

py/conftest.py

@@ -349,6 +349,8 @@ def driver(request):
     yield selenium_driver.driver
 
     if request.node.get_closest_marker("no_driver_after_test"):
+        if selenium_driver is not None:
+            selenium_driver.stop_driver()
         selenium_driver = None