style(fetcher): Move the default UA line

scrapling/engines/static.py

@@ -30,10 +30,9 @@ from .toolbelt import (
     generate_convincing_referer,
     generate_headers,
     ResponseFactory,
+    __default_useragent__,
 )
 
-__default_useragent__ = generate_headers(browser_mode=False).get("User-Agent")
-
 
 class FetcherSession:
     """