Add try-catch block to detect when length of the array is zero

[jicowan]

If the nodes are not properly tainted, the daemon will throw an error when it gets here. We need to add a try-catch block to a) add the missing taint agones.dev/game-servers or b) throw an error or c) both.

https://github.com/awslabs/fleetiq-adapter-for-agones/blob/56bae655a1fac7db4ffcf341b3a7ccf070fec9da/gamelift-daemon/src/main.py#L97