Summary: Change ThreadID to long

Test Plan:
Messages should send and receive as before. Additionally, if your device has assigned extremely large ThreadIDs, the SMS plugin should no longer crash.

This patch corresponds to the Android-side revision D17517

Reviewers: #kde_connect, nicolasfella

Reviewed By: #kde_connect, nicolasfella

Subscribers: nicolasfella, kdeconnect

Tags: #kde_connect

Differential Revision: https://phabricator.kde.org/D17516