Expose set_device_event_filter to Tauri API

[Godnoken]

Describe the problem

When using rdev and possibly other global shortcut crates, the keyboard input gets blocked by DeviceEventFilter default state Unfocused if the Tauri app is in focus. #https://github.com/tauri-apps/tao/commit/5bbd4f8f72901425432a35915d79d0bee0c96cce

Describe the solution you'd like

Expose set_device_event_filter function to the Tauri API so devs can set it for themselves. In my case, setting it to Always solved the problem.

Additional context

Only tested on Windows 10.