client: Application.Controller: Disable flood prevention after a small timeout
Marking a message with same command is legit in those scenarios:
- Previous mark command failed, we do not want Geary to be unable to mark message again
- Multiple clients connected to same IMAP box:
- Geary marked message as read
- Another client marked it as unread
- Geary is unable to mark it as read again
Edited by Cédric Bellegarde