fix: Ensure database route table output works (#926)

* fix: ensure database route table output works

On initial plan the `database_route_table_ids` output is not
available due to the values not being known until after apply.
Switching the logic to test the length of the array fixes this
issue. Credit to @martin566 for discovering the solution.

fixes #857

* Update outputs.tf

* Update outputs.tf

---------

Co-authored-by: Bryant Biggs <bryantbiggs@gmail.com>

outputs.tf

@@ -279,7 +279,8 @@ output "database_subnet_group_name" {
 
 output "database_route_table_ids" {
   description = "List of IDs of database route tables"
-  value       = try(coalescelist(aws_route_table.database[*].id, local.private_route_table_ids), [])
+  # Refer to https://github.com/terraform-aws-modules/terraform-aws-vpc/pull/926 before changing logic
+  value = length(aws_route_table.database[*].id) > 0 ? aws_route_table.database[*].id : aws_route_table.private[*].id
 }
 
 output "database_internet_gateway_route_id" {