[py] Remove ability to set env var for SE_SAFARIDRIVER

Author: cgoldberg

py/selenium/webdriver/safari/service.py

@@ -47,7 +47,6 @@ def __init__(
         **kwargs,
     ) -> None:
         self.service_args = service_args or []
-        driver_path_env_key = driver_path_env_key or "SE_SAFARIDRIVER"
 
         if enable_logging:
             self.service_args.append("--diagnose")