TGTCheckAction throws Exception with invalid TGT

The existing TGTAction check attempts to find the TGT present in the context from the registry via:

```java
final Ticket ticket = this.centralAuthenticationService.getTicket(tgtId, Ticket.class);
```

This throws exceptions if ticket id not found. This pull handles the catching of that exception.
I really like to see a ```@since``` in every class.