Hotfix: Bumping integration testing timeout to compensate for recent bugfix

[cmcginley-splunk]

Context

• in Adding risk message validation++ #92 we introduced a bugfix which shaved an unnecessary extra 60s wait before starting the backoff timer
• this resulted in less overall time for those detections which are sluggish to generate risk events, causing some intermittent failures

Code changes

• we bumped the total backoff timer by 60s (from 210s to 270s)

[pyth0n1c]

Agreed with this change. This amount gives us a bit larger margin and should cut our failures to 0. If we continue to see timing issues, we can bump this even higher.