libusb and runtime/sdk related questions

**libusb** is part of the Freedesktop runtime version **25.08**. KDE runtime **5.15-25.08** and **6.10** inherit this runtime.

I'm not entirely sure because it's a plugin, but you'll likely be able to remove this module when you upgrade the OBS runtime version to 6.10.

I have limited knowledge about plugins; from what I understand, you're using a different SDK version than the main project. Please consider synchronizing the runtime/SDK version with the SDK version used by the main project.

```
LC_ALL=C flatpak remote-info flathub --system com.obsproject.Studio

OBS Studio - Live stream and record videos

ID: com.obsproject.Studio
Ref: app/com.obsproject.Studio/x86_64/stable
Runtime: org.kde.Platform/x86_64/6.8
Sdk: org.kde.Sdk/x86_64/6.8
```

/Google translate