[Folder View] In list view mode, fix home button disappearing every other subfolder entered

Test Plan:
Add a Folder View in a panel, open it in "list view" mode.
Navigate through several subfolders: the 'home' button that appears in the top left corner of the applet should not disappear every even number of subfolder you open.

Reviewers: #plasma, #vdg, hein

Reviewed By: #plasma, hein

Subscribers: abetts, hein, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D15823