Update the aws_lb_target_group to use the new healthcheck endpoint

[jimmie]

💡 Description

Once the PR for the healthcheck has been approved, merged and deployed, the health_check for the load balancer target group(s) should be updated to leverage it. Namely, these lines should be updated to specify:

health_check {
    enabled = true
    path    = "/healthcheck"
    matcher = "200"
    interval = 60
  }