Change CI tests to use us-east-2 to validate multi-region support

Using a non-us-east-1 region ensures the tests validate that:
- ACM certificates are created in the correct region (same as ALB)
- DNS query logging resources are correctly created in us-east-1
  despite the default region being different

Author: Sean Thomas

.github/workflows/template-only-ci-infra.yml

@@ -88,7 +88,7 @@ jobs:
       - name: Configure AWS credentials
         uses: aws-actions/configure-aws-credentials@v4
         with:
-          aws-region: us-east-1
+          aws-region: us-east-2
 
           # Use access key credentials for the template infra test workflow
           # instead of using GitHub OIDC because only one GitHub OIDC provider