klipper: fix popup not following size of active screen on Wayland
Reason for the change
The window needs to be resized before it becomes visible on Wayland.
Test plan
- Connect to two screens and set different resolutions
- Press Meta+V on the two screens and the popup size should follow the active screen
Screenshots or screen recordings
Bugs fixed
BUG: 495987 FIXED-IN: 6.4
Edited by Fushan Wen