Only show full name in review dialog

Summary:
The review gets submitted with your full name, but the review dialog currently shows
both the full name and username. This patch removes the username display so that it shows
the actual name string that will be used.

Test Plan:
Before: {F7860875}
After: {F7860874}

Reviewers: #discover_software_store, apol

Reviewed By: #discover_software_store, apol

Subscribers: jgrulich, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D26421