Make isort compatible with black

isort's lines_after_imports = 2 conflicted with black, so run-cleanup
reverted black's changes. Use isort's black profile instead and apply the
resulting formatting. Also fix the flake8 errors in check_email_mixin and
drop a leftover debug print.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

max/csrf.py

@@ -5,7 +5,6 @@ from flask import request, session
 from max.crypto import constant_time_compare, get_random_string
 from max.middlewares import BaseMiddleware
 
-
 CSRF_TOKEN_KEY = "csrf_token"
 CSRF_TOKEN_LENGTH = 32