Remove artifact while navigating though pages

When the view is paged (ie, non continuous), and an annotation is
selected while the user navigate through pages, the annotation
selection will become an artifact in other pages. Besides that,
the annotation will still receive keystrokes (such as delete).

Steps to Reproduce:
 - Open a PDF file with Okular
 - Draw an ellipsis annotation in the document
 - Select the ellipsis
 - Change to the previous or next page
2 jobs for master in 32 minutes and 18 seconds (queued for 14 minutes and 1 second)
Status Job ID Name Coverage
passed #66278


passed #66277
linux kf5-qt5 qt5.12