Return LE_DUPLICATE if session with AirVantage is already disconnected
Return LE_DUPLICATE if session with AirVantage is already disconnected

Resolves: LE-8270
Change-Id: Id43cf5653346df62785c2f1617b6c23325b56e60

legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af