Creating `stackit_security_group_rule` accepting any ports results in inconsistent state

[albgus]

Description

Creating a stackit_security_group_rule with port_range with max and min values set to 0 results in an inconsistent result after apply in Terraform.

After creation It looks correct in the web interface though where 0 is displayed Start-port: Any

Steps to reproduce

Apply the following Terraform

resource "stackit_security_group" "this" {
  project_id = var.project_id

  name        = "repro"
}
resource "stackit_security_group_rule" "this" {
  project_id = var.project_id

  security_group_id = stackit_security_group.this.security_group_id

  direction  = "ingress"
  ether_type = "IPv4"

  protocol = {
    name = "tcp"
  }
  port_range = {
    max    = 0
    min    = 0
  }

  ip_range                 = "10.0.0.0/8"
}

Actual behavior

╷
│ Error: Provider produced inconsistent result after apply
│ 
│ When applying changes to stackit_security_group_rule.this, provider "provider[\"registry.terraform.io/stackitcloud/stackit\"]" produced an unexpected new value: .port_range: was
│ cty.ObjectVal(map[string]cty.Value{"max":cty.NumberIntVal(0), "min":cty.NumberIntVal(0)}), but now null.
│ 
│ This is a bug in the provider, which should be reported in the provider's own issue tracker.
╵

Expected behavior

A security group with source ports Any: Any is created

Environment

Terraform v1.9.8
on darwin_arm64
+ provider registry.terraform.io/stackitcloud/stackit v0.67.0

[rubenhoenle]

Most likely the same problem as in #788