Move Folders item closer to the top

Summary:
Move Folders item closer to the top in Dolphin's find panel. This seems like a more natural placment than after the document types.

Also re-order variable placement to maintain consistency

Test Plan:
Tested in KDE Neon; works. Before:
{F4631565}

After:
{F4631532}

Reviewers: #dolphin, elvisangelaccio

Reviewed By: #dolphin, elvisangelaccio

Subscribers: #dolphin

Differential Revision: https://phabricator.kde.org/D8132