Plugging a screen confines the cursor

Preparation:

x86_64 Debian Testing with Purism CI repo, librem5-gnome installed, purism user, AMD GPU, DVI display attached

Execution:

1. Attach a HDMI screen (dev board adapter)
2. Start phosh

Result:

Mouse pointer is restricted to the HDMI screen

Expected result:

Both screens are positioned side-by-side from the POV of the mouse pointer, allowing it to move from one to another seamlessly

Workaround:

If the HDMI screen was attached later, the UI will stay on the unreachable one. Disconnect the newly attached screen to go back to the first one.