Change Installed list icon to view-list-details

Summary: The previous icon was the same, but it was blurry because it was only 16px

Test Plan:
Old: {F7309070, size=full}
New: {F7309069, size=full}

Reviewers: #vdg, #discover_software_store, ngraham

Reviewed By: #vdg, #discover_software_store, ngraham

Subscribers: ngraham, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D23678