Fix Plasma crash when left click on unconfigured Person plasmoid

Summary

when left click on unconfigured Person plasmoid - plasmashell segfaulted.
plasmashell 5.12.6

kf5-kpeople-devel-5.47
kde5-ktp-desktop-applets-18.04.2

Test Plan

Add Person plasmoid to desktop.
Do left click on it (plasmoid).
segmentation faults...

Differential Revision: https://phabricator.kde.org/D14232