[Properties dialog] Improve some permissions-related strings

Summary:
BUG: 96714
FIXED-IN: 5.48

Improve some permissions-related strings to be clearer.

Test Plan:
File:
{F5913210}

Folder:
{F5913211}

Reviewers: #frameworks, #vdg, #dolphin

Subscribers: abetts, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D13552