Remove KDE3 reference in kdeeject

Summary:
There is no org.kde.kdesktop and we don't show mount points by default
on the desktop so there's nothing to explicitly refresh.

BUG: 357986

Test Plan: None

Reviewers: Plasma, apol

Reviewed By: apol

Subscribers: plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D17717