Don't reset model when available connection appears
Summary:
addAvailableConnection() does the proper row/data update handling already
Depends on D24920
Test Plan: Opened a new Wifi, it appeared in the plasmoid
Reviewers: jgrulich
Reviewed By: jgrulich
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D24922