Make load balancer internal when vpc is not managed through CiviForm

[dkatzz]

Description

If we don't do this, we get an error:

│ Error: creating ELBv2 application Load Balancer (charlotte-vpc10-civiform-lb): InvalidSubnet: VPC vpc-0f18a363a62cc1675 has no internet gateway
│       status code: 400, request id: f09051a2-e2fe-4b4d-9bc5-c80ba8f2d009
│ 
│   with module.ecs_fargate_service.aws_lb.civiform_lb,
│   on ../../modules/ecs_fargate_service/[main.tf](http://main.tf/) line 26, in resource "aws_lb" "civiform_lb":
│   26: resource "aws_lb" "civiform_lb" {

This is needed for Charlotte's deployment. We could also decide to make this a separate variable from the vpc changes, or can do that in the future if they no longer should be tied together.

Checklist

General

• Added the correct label
• Assigned to a specific person or civiform/deployment-system
• Performed manual testing (at a minimum run bin/setup without your changes and then bin/deploy with your changes to ensure your changes don't break existing deployments)

Instructions for manual testing

Tested by deploying in the charlotte test environment with the config from this branch and tested to ensure this didn't change anything in an existing environment

Issue(s) this completes

civiform/civiform#7648