Don't use a scrollview to display package changelogs
Summary:
BUG: 387036
Don't put the package changelogs in a scrollview, because it introduces some usability issues (see the bug for details).
Also change the "Open" button to day "More Information..." since it wasn't clear what you were opening.
Test Plan:
Tested in KDE Neon. Package changelogs are now fully visible without being in a tiny scrollview:
Reviewers: Discover Software Store, apol
Reviewed By: Discover Software Store, apol
Subscribers: abetts, broulik, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D8869