fix(EmailDeliveryService): Send message as str for spam check

press/api/email.py

@@ -170,7 +170,7 @@ def send_mime_mail(**data):
  api_key, domain = frappe.db.get_value("Press Settings", None, ["mailgun_api_key", "root_domain"])
 
  message = files["mime"].read()
- check_spam(message)
+ check_spam(message.decode("utf-8"))
 
  resp = requests.post(
  f"https://api.mailgun.net/v3/{domain}/messages.mime",