[Bug]: OS wrong result for discTitles

[Tolriq]

I confirm that:

• [X] I have searched the existing open AND closed issues to see if an issue already exists for the bug I've encountered
• [X] I'm using the latest version (your issue may have been fixed already)

Version

0.51.01

Current Behavior

Returns invalid data: "discTitles":[{"disc":1}]

Expected Behavior

The title field is required as per the spec.

Steps To Reproduce

No response

Environment

- OS:
- Browser:
- Client:

How Navidrome is installed?

Binary (from downloads page)

Configuration

No response

Relevant log output

No response

Anything else?

No response

Code of Conduct

• [X] I agree to follow Navidrome's Code of Conduct