Export: "Other..." sample rate option is missing

In the list dropdown of available sample rate options, there should be "Other...", clicking which should open a dialog allowing the entry of a custom sample rate value. 

### AU3:
<img width="548" height="435" alt="Image" src="https://github.com/user-attachments/assets/e8e8aa7f-438e-493a-b7b8-6aa944f0fefe" />