Remove clipboard integration on the plasmoid

It's redundant to the clipboard plugin and remote keyboard.
It clutters the UI.

Reviewed by Albert Vaca
2 jobs for master in 9 minutes and 46 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #18497
linux kf5-qt5 qt5.12

00:08:18

34.0%
passed #18498
windows
windows kf5-qt5 qt5.13

00:09:46