Show Date Modified information by default in Dolphin's Information Panel and Tooltips

Summary:
BUG: 381470

Show Date Modified information by default in Dolphin's Information Panel and Tooltips.

Test Plan:
Tested in KDE Neon. Works; a fresh install using a clean baloofileinformationrc file results in Date Modified appearing in the Information Panel and Tooltips by default:

Reviewers: Dolphin, KDE Applications, Frameworks, aacid, markg

Reviewed By: markg

Subscribers: markg, elvisangelaccio, anthonyfieroni

Tags: Dolphin

Differential Revision: https://phabricator.kde.org/D8303