fix(lambda): add post-deregister busy check to prevent terminating active runners#5086

JVenberg wants to merge 1 commit intogithub-aws-runners:maingithub-aws-runners/terraform-aws-github-runner:mainfrom

JVenberg:fix/scale-down-busy-check-race-conditionJVenberg/terraform-aws-github-runner:fix/scale-down-busy-check-race-conditionCopy head branch name to clipboard