Fix initial deploy invalid count dependency error

Description

Fixing #16 - which happens due to the code below

# modules/opennext-cloudfront/waf.tf
resource "aws_wafv2_web_acl" "cloudfront_waf" {
  count = var.custom_waf == null ? 1 : 0
  ...
}

resouce "aws_wafv2_web_acl_logging_configuration" "waf_logging" {
  count = var.waf_logging_configuration == null || try(aws_wafv2_web_acl.cloudfront_waf[0], null) == null ? 0 : 1
  ...
}

If you reference another resource in the count argument, terraform will fail on initial deploy because that other resource won't exist yet, so the count argument is not yet defined, but terraform needs the count argument to be defined for a deploy.

All the code is trying to do is deploy aws_wafv2_web_acl_logging_configuration.waf_logging only if the aws_wafv2_web_acl.cloudfront_waf exists (has count > 0). We can do this without causing this terraform error by simply placing the condition in the count for aws_wafv2_web_acl.cloudfront_waf inside of aws_wafv2_web_acl_logging_configuration.waf_logging's count condition.

Like this:

resource "aws_wafv2_web_acl_logging_configuration" "waf_logging" {
  count = var.waf_logging_configuration == null || var.custom_waf != null ? 0 : 1

  ...
}

Context

Issue #16

Type of changes

[x] Refactoring (non-breaking change)
[ ] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would change existing functionality)
[x] Bug fix (non-breaking change which fixes an issue)

Checklist

[ ] I am familiar with the contributing guidelines
[x] I have followed the code style of the project
[ ] I have added tests to cover my changes
[ ] I have updated the documentation accordingly
[ ] This PR is a result of pair or mob programming

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nhs-england-tools / terraform-aws-opennext