Action: MailboxCount
Synopsis: Check Mailbox Message Count
Privilege: call,all
Description: Checks a voicemail account for new messages.
Variables: (Names marked with * are required)
       *Mailbox: Full mailbox ID <mailbox>@<vm-context>
       ActionID: Optional ActionID for message matching.
Returns number of new and old messages.
       Message: Mailbox Message Count
       Mailbox: <mailboxid>
       NewMessages: <count>
       OldMessages: <count>
Command Example: