[BUG] Manually removed records are not detected

[project0]

Checklist

• [x] I have used the latest version of terraform (if not please provide a version number).
• [x] I have used the latest version of this terraform provider (if not please provide a version number).
• [ ] I have provided a sample .tf configuration under "Additional context".
• [ ] I have answered the following question: Is this issue reproducible in OT&E or only applies to live?

Describe the bug

When a nameserver record is being removed manually (for example via the web console), the terraform provider is not detecting the change and assumes everything is ok.

Changing the content manually seem to be detect and is fine, so i wonder why not found resources are not detected.

To Reproduce Steps to reproduce the behavior:

1. create a record with inwx_nameserver_record
2. apply change
3. delete record manually
4. apply/plan terraform (no change)

Expected behavior Re-creation of the missing resource (dns record)

[project0]

Also deleting the entry and updating the resource in terraform does not detect missing resource, apply wents through without any error.