Fix/multiple app clients issue

[p-golovkin]

Fixes following error during terraform plan with multiple app-clients defined:

│ on .terraform/modules/console_ui_cognito_user_pool/main.tf line 214, in resource "aws_cognito_user_pool_client" "client":
│ 214: for_each = var.module_enabled ? local.clients : {}
│ ├────────────────
│ │ local.clients is object with 2 attributes
│ │ var.module_enabled is true
│
│ The true and false result expressions must have consistent types. The
│ 'true' value includes object attribute "auto-test-app", which is absent in
│ the 'false' value.