Do not overwrite default for username with email address in FlaskIntegration (#1873)

This line seems like a copy/paste error, introduced in 4112000.

Co-authored-by: Neel Shah <[email protected]>

Author: homeworkprod

sentry_sdk/integrations/flask.py

@@ -261,6 +261,5 @@ def _add_user_to_event(event):
 
         try:
             user_info.setdefault("username", user.username)
-            user_info.setdefault("username", user.email)
         except Exception:
             pass