Recognize anonymous group messages as administrative

[Syfaro]

When performing commands that require administrative permissions, the bot attempts to validate that the sending user has administrative permissions in the chat (either through the permission cache or by calling the API). If the message was sent anonymously as the chat, the bot doesn't recognize the user as privileged (it's always from ID 1087968824). Because these anonymous messages can only be sent by admins, they should be recognized as being sent from a privileged user.