Make update page labels consistent with topUpdateComp
Summary: Made the labels on the update page consistent with the ones shown in the topUpdateComp of the main window
Test Plan: Check for updates and see that the labels have changed
Reviewers: Discover Software Store, ngraham
Reviewed By: Discover Software Store, ngraham
Subscribers: apol, ngraham, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D23292