Passkey not working for some sites when created from desktop.

### Checks

- [x] I have read the Wiki, searched the open issues, and still think this is a new bug.

### Explain the problem clearly and succinctly:

The problem is with https://www.target.com/ specifically, every other passkey I have works on XC and DX flawlessly. I created a passkey on firefox on my linux desktop, waited for my database to sync to my phone and tried it there. I get "We couldn't sign you in with that passkey" on firefox mobile. I am still able to use it on the same desktop on other browsers and my laptop.

### Describe what you expected to happen:

When clicking "Sign in with passkey" the target website accepts the login as it does on desktop.

### KeePassDX version:

4.2.4

### Build:

Libre

### Database version:

V2 - KBDX4.1

### File provider (`content://` URI)

_No response_

### Android version:

15

### Android device:

Samsung Galaxy S21

### Additional context:

_No response_

Reproduce the passkey sign-in flow on target.com using Firefox Mobile on Android 15 with a Samsung Galaxy S21, after creating the passkey on Firefox desktop and syncing the database. Compare the failing mobile behavior with successful sign-in on the desktop and other browsers; done means the target.com passkey is accepted on mobile.

Written by the indexing model from the issue text.