Retry wait for stable service in deploy release (#761)

## Ticket

n/a

## Changes
- If waiting for a stable ECS service fails during deploy, try it
exactly one more time

## Context for reviewers
- For two applications using the template-infra, the Nava Labs Decision
Support Tool project, and an internal Nava tool, the ECS service takes
slightly more than 10 minutes to become stable (typically about 11 or
13).
- The AWS wait command can't be configured to allow more than 10 minutes
 - Other approaches considered:
- Sleeping. This is probably the simplest solution but doesn't seem as
robust as simply trying the command twice.
- Retrying a configurable number of times in a loop. This seems like
premature complexity.

## Testing
Tested on internal tool (posted in Slack)

bin/deploy-release

@@ -25,6 +25,13 @@ echo "::endgroup::"
 cluster_name=$(terraform -chdir="infra/${app_name}/service" output -raw service_cluster_name)
 service_name=$(terraform -chdir="infra/${app_name}/service" output -raw service_name)
 echo "Wait for service ${service_name} to become stable"
-aws ecs wait services-stable --cluster "${cluster_name}" --services "${service_name}"
+wait_for_service_stability() {
+  aws ecs wait services-stable --cluster "${cluster_name}" --services "${service_name}"
+}
+
+if ! wait_for_service_stability; then
+  echo "Retrying"
+  wait_for_service_stability
+fi
 
 echo "Completed ${app_name} deploy of ${image_tag} to ${environment}"