I had the same issue last night. My Dev APNs are gone and can't re-upload, i got the same error as you.
And immediately send and feedback / ticket to Firebase Support. It's an issue from their end, and already fixed and pushed to production they said.
Now my Dev APNs are back.
Here's the latest reply from Firebase Support Team
Hello Bagus,
This issue has been fixed from our end and the fix has been pushed to
production. You should be able to upload the Development APNs
certificates without issues.
Although, feel free to let us know if the issue persists or if you
have any additional questions we can help with.
Thank you for using Firebase! Karishma