Imported DNS access does not trigger modifications when setting is empty

[gmichels]

Given the pre-populated DNS allowed list in ADG:

client1
client2
client3

When importing the resource with the bare-minimum configuration:

resource "adguard_dns_access" "test" {
}

A subsequent terraform plan does not trigger a modification of the allow list as expected.

$ terraform plan -target=adguard_dns_access.test
adguard_dns_access.external: Refreshing state... [id=1]

No changes. Your infrastructure matches the configuration.

Terraform has compared your real infrastructure against your configuration and found no differences, so no changes are needed.

Provider should empty the allowed list as nothing is declared.